diff --git a/www/src/brython.js b/www/src/brython.js
index ecfbb818a..3f4d35393 100644
--- a/www/src/brython.js
+++ b/www/src/brython.js
@@ -209,8 +209,8 @@ $B.unicode_bidi_whitespace=[9,10,11,12,13,28,29,30,31,32,133,5760,8192,8193,8194
 ;
 __BRYTHON__.implementation=[3,13,1,'dev',0]
 __BRYTHON__.version_info=[3,13,0,'final',0]
-__BRYTHON__.compiled_date="2024-11-05 10:25:30.265416"
-__BRYTHON__.timestamp=1730798730264
+__BRYTHON__.compiled_date="2024-11-05 13:35:50.668375"
+__BRYTHON__.timestamp=1730810150668
 __BRYTHON__.builtin_module_names=["_ajax","_ast","_base64","_binascii","_io_classes","_json","_jsre","_locale","_multiprocessing","_posixsubprocess","_profile","_random","_sre","_sre_utils","_string","_strptime","_svg","_symtable","_tokenize","_webcomponent","_webworker","_zlib_utils","_zlib_utils1","_zlib_utils_kozh","array","builtins","dis","encoding_cp932","encoding_cp932_v2","hashlib","html_parser","marshal","math","modulefinder","posix","pyexpat","python_re","python_re_new","unicodedata","xml_helpers","xml_parser","xml_parser_backup"]
 ;
 
@@ -283,9 +283,16 @@ return code}
 function $last(array){return array[array.length-1]}
 var ops='.,:;+-*/%~^|&=<>[](){}@',
 op2=['**','//','>>','<<'],augm_op='+-*/%^|&=<>@',closing={'}':'{',']':'[',')':'('}
+function ErrorToken(){var args=Array.from(arguments)
+args.$error_token=true
+return args}
+function ErrorTokenKnownToken(){var args=Array.from(arguments)
+args.$error_token_known_token=true
+return args}
 function Token(type,string,lineno,col_offset,end_lineno,end_col_offset,line){var res={type,string,line,lineno,col_offset,end_lineno,end_col_offset}
 res.num_type=$B.py_tokens[type]
-if(type=='OP'){res.num_type=$B.py_tokens[$B.EXACT_TOKEN_TYPES[string]]}else if(type=='ENCODING'){res.num_type=$B.py_tokens.ENCODING}
+if(type=='OP'){res.num_type=$B.py_tokens[$B.EXACT_TOKEN_TYPES[string]]}else if(type=='ENCODING'){
+res.parser_ignored=true}else if(type=='NL' ||type=='COMMENT'){res.parser_ignored=true}
 res.bytes=res.string 
 return res}
 function get_comment(parser,src,pos,line_num,line_start,token_name,line){var start=pos,ix
@@ -319,7 +326,7 @@ function nesting_level(token_modes){var ix=token_modes.length-1
 while(ix >=0){var mode=token_modes[ix]
 if(mode.nesting !==undefined){return mode.nesting}
 ix--}}
-$B.tokenizer=function*(src,filename,mode,parser){var string_prefix=/^(r|u|R|U|f|F|fr|Fr|fR|FR|rf|rF|Rf|RF)$/,bytes_prefix=/^(b|B|br|Br|bR|BR|rb|rB|Rb|RB)$/
+$B.tokenizer=function(src,filename,mode,parser){var string_prefix=/^(r|u|R|U|f|F|fr|Fr|fR|FR|rf|rF|Rf|RF)$/,bytes_prefix=/^(b|B|br|Br|bR|BR|rb|rB|Rb|RB)$/,t=[]
 if(mode !='eval' && ! src.endsWith('\n')){src+='\n'}
 var lines=src.split('\n'),linenum=0,line_at={}
 for(let i=0,len=src.length;i < len;i++){line_at[i]=linenum
@@ -327,7 +334,7 @@ if(src[i]=='\n'){linenum++}}
 function get_line_at(pos){return lines[line_at[pos]]+'\n'}
 var state="line_start",char,cp,mo,pos=0,quote,triple_quote,escaped=false,string_start,string,prefix,name,number,num_type,comment,indent,indent_before_continuation=0,indents=[],braces=[],line,line_num=0,line_start=1,token_modes=['regular'],token_mode='regular',save_mode=token_mode,fstring_buffer,fstring_start,fstring_expr_start,fstring_escape,format_specifier
 if(parser){parser.braces=braces}
-yield Token('ENCODING','utf-8',0,0,0,0,'')
+t.push(Token('ENCODING','utf-8',0,0,0,0,''))
 while(pos < src.length){char=src[pos]
 cp=src.charCodeAt(pos)
 if(cp >=0xD800 && cp <=0xDBFF){
@@ -346,8 +353,8 @@ continue}
 char=token_mode.quote.repeat(3)
 pos+=2}
 if(fstring_buffer.length > 0){
-yield Token(FSTRING_MIDDLE,fstring_buffer,line_num,fstring_start,line_num,fstring_start+fstring_buffer.length,line)}
-yield Token(FSTRING_END,char,line_num,pos-line_start,line_num,pos-line_start+1,line)
+t.push(Token(FSTRING_MIDDLE,fstring_buffer,line_num,fstring_start,line_num,fstring_start+fstring_buffer.length,line))}
+t.push(Token(FSTRING_END,char,line_num,pos-line_start,line_num,pos-line_start+1,line))
 token_modes.pop()
 token_mode=$B.last(token_modes)
 state=null
@@ -355,7 +362,7 @@ continue}else if(char=='{'){if(src.charAt(pos)=='{'){
 fstring_buffer+=char
 pos++
 continue}else{
-if(fstring_buffer.length > 0){yield Token(FSTRING_MIDDLE,fstring_buffer,line_num,fstring_start,line_num,fstring_start+fstring_buffer.length,line)}
+if(fstring_buffer.length > 0){t.push(Token(FSTRING_MIDDLE,fstring_buffer,line_num,fstring_start,line_num,fstring_start+fstring_buffer.length,line))}
 token_mode='regular_within_fstring'
 fstring_expr_start=pos-line_start
 state=null
@@ -363,7 +370,7 @@ token_modes.push(token_mode)}}else if(char=='}'){if(src.charAt(pos)=='}'){
 fstring_buffer+=char
 pos++
 continue}else{
-yield Token('OP',char,line_num,pos-line_start,line_num,pos-line_start+1,line)
+t.push(Token('OP',char,line_num,pos-line_start,line_num,pos-line_start+1,line))
 continue}}else if(char=='\\'){if(token_mode.raw){fstring_buffer+=char+char}else{if(fstring_escape){fstring_buffer+='\\'+char}
 fstring_escape=! fstring_escape}
 continue}else{if(fstring_escape){fstring_buffer+='\\'}
@@ -371,17 +378,17 @@ fstring_buffer+=char
 fstring_escape=false
 if(char=='\n'){line_num++}
 continue}}else if(token_mode=='format_specifier'){if(char==quote){if(format_specifier.length > 0){
-yield Token(FSTRING_MIDDLE,format_specifier,line_num,fstring_start,line_num,fstring_start+format_specifier.length,line)
+t.push(Token(FSTRING_MIDDLE,format_specifier,line_num,fstring_start,line_num,fstring_start+format_specifier.length,line))
 token_modes.pop()
 token_mode=$B.last(token_modes)
 continue}}else if(char=='{'){
-yield Token(FSTRING_MIDDLE,format_specifier,line_num,fstring_start,line_num,fstring_start+format_specifier.length,line)
+t.push(Token(FSTRING_MIDDLE,format_specifier,line_num,fstring_start,line_num,fstring_start+format_specifier.length,line))
 token_mode='regular_within_fstring'
 fstring_expr_start=pos-line_start
 state=null
 token_modes.push(token_mode)}else if(char=='}'){
-yield Token(FSTRING_MIDDLE,format_specifier,line_num,fstring_start,line_num,fstring_start+format_specifier.length,line)
-yield Token('OP',char,line_num,pos-line_start,line_num,pos-line_start+1,line)
+t.push(Token(FSTRING_MIDDLE,format_specifier,line_num,fstring_start,line_num,fstring_start+format_specifier.length,line))
+t.push(Token('OP',char,line_num,pos-line_start,line_num,pos-line_start+1,line))
 if(braces.length==0 ||$B.last(braces).char !=='{'){throw Error('wrong braces')}
 braces.pop()
 token_modes.pop()
@@ -393,20 +400,19 @@ line=get_line_at(pos-1)
 line_start=pos
 line_num++
 if(mo=/^\f?(\r\n|\r|\n)/.exec(src.substr(pos-1))){
-yield Token('NL',mo[0],line_num,0,line_num,mo[0].length,line)
+t.push(Token('NL',mo[0],line_num,0,line_num,mo[0].length,line))
 pos+=mo[0].length-1
 continue}else if(char=='#'){comment=get_comment(parser,src,pos,line_num,line_start,'NL',line)
-for(var item of comment.t){yield item}
+for(var item of comment.t){t.push(item)}
 pos=comment.pos
 state='line_start'
 continue}
 indent=0
 if(char==' '){indent=1}else if(char=='\t'){indent=8}
 if(indent){var broken=false
-while(pos < src.length){if(broken && indent > 0 && ' \t'.includes(src[pos])){console.log('indentation error 479')
-$B.raise_error_known_location(
-_b_.IndentationError,filename,line_num,pos-line_start,line_num,pos-line_start+1,line,'unindent does not match any outer indentation level'
-)}
+while(pos < src.length){if(broken && indent > 0 && ' \t'.includes(src[pos])){t.push(ErrorToken(
+_b_.IndentationError,filename,line_num,pos-line_start,line_num,pos-line_start+1,line,'unindent does not match any outer indentation level'))
+return t}
 if(src[pos]==' '){indent++}else if(src[pos]=='\t'){indent+=8}else if(src[pos]=='\\' && src[pos+1]=='\n'){
 pos++
 line_start=pos+2
@@ -419,24 +425,26 @@ line_num--
 break}
 if(src[pos]=='#'){
 comment=get_comment(parser,src,pos+1,line_num,line_start,'NL',line)
-for(var item of comment.t){yield item}
+for(var item of comment.t){t.push(item)}
 pos=comment.pos
 continue}else if(src[pos]=='\\'){if(/^\f?(\r\n|\r|\n)/.exec(src[pos+1])){line_num++
 pos++
-continue}else{$B.raise_error_known_location(_b_.SyntaxError,filename,line_num,pos+2-line_start,line_num,pos+3-line_start,line,'unexpected character after line continuation character')}}else if(mo=/^\f?(\r\n|\r|\n)/.exec(src.substr(pos))){
-yield Token('NL','',line_num,pos-line_start+1,line_num,pos-line_start+1+mo[0].length,line)
+continue}else{t.push(ErrorToken(_b_.SyntaxError,filename,line_num,pos+2-line_start,line_num,pos+3-line_start,line,'unexpected character after line continuation character'))
+return t}}else if(mo=/^\f?(\r\n|\r|\n)/.exec(src.substr(pos))){
+t.push(Token('NL','',line_num,pos-line_start+1,line_num,pos-line_start+1+mo[0].length,line))
 pos+=mo[0].length
 continue}
 if(indents.length==0 ||indent > $last(indents)){indents.push(indent)
-yield Token('INDENT','',line_num,0,line_num,indent,line)}else if(indent < $last(indents)){var ix=indents.indexOf(indent)
+t.push(Token('INDENT','',line_num,0,line_num,indent,line))}else if(indent < $last(indents)){var ix=indents.indexOf(indent)
 if(ix==-1){var message='unindent does not match '+
 'any outer indentation level'
-$B.raise_error_known_location(_b_.IndentationError,filename,line_num,0,line_num,0,line,message)}
+t.push(ErrorToken(_b_.IndentationError,filename,line_num,0,line_num,0,line,message))
+return t}
 for(var i=indents.length-1;i > ix;i--){indents.pop()
-yield Token('DEDENT','',line_num,indent,line_num,indent,line)}}
+t.push(Token('DEDENT','',line_num,indent,line_num,indent,line))}}
 state=null}else{
 while(indents.length > 0){indents.pop()
-yield Token('DEDENT','',line_num,indent,line_num,indent,line)}
+t.push(Token('DEDENT','',line_num,indent,line_num,indent,line))}
 state=null
 pos--}
 break
@@ -455,7 +463,7 @@ break
 case '#':
 var token_name=braces.length > 0 ? 'NL' :'NEWLINE'
 comment=get_comment(parser,src,pos,line_num,line_start,token_name,line)
-for(var item of comment.t){yield item}
+for(var item of comment.t){t.push(item)}
 pos=comment.pos
 if(braces.length==0){state='line_start'}else{state=null
 line_num++
@@ -475,7 +483,8 @@ continue}
 let msg='leading zeros in decimal integer '+
 'literals are not permitted; use an 0o prefix '+
 'for octal integers'
-$B.raise_error_known_location(_b_.SyntaxError,filename,line_num,pos-line_start-number.length,line_num,pos-line_start,line,msg)}else{break}}}
+t.push(ErrorToken(_b_.SyntaxError,filename,line_num,pos-line_start-number.length,line_num,pos-line_start,line,msg))
+return t}else{break}}}
 break
 case '.':
 if(src[pos]&& $B.in_unicode_category('Nd',ord(src[pos]))){state='NUMBER'
@@ -485,28 +494,30 @@ while(src[pos]==char){pos++
 op+=char}
 var dot_pos=pos-line_start-op.length+1
 while(op.length >=3){
-yield Token('OP','...',line_num,dot_pos,line_num,dot_pos+3,line)
+t.push(Token('OP','...',line_num,dot_pos,line_num,dot_pos+3,line))
 op=op.substr(3)}
-for(var i=0;i < op.length;i++){yield Token('OP','.',line_num,dot_pos,line_num,dot_pos+1,line)
+for(var i=0;i < op.length;i++){t.push(Token('OP','.',line_num,dot_pos,line_num,dot_pos+1,line))
 dot_pos++}}
 break
 case '\\':
 var mo=/^\f?(\r\n|\r|\n)/.exec(src.substr(pos))
 if(mo){if(pos==src.length-1){var msg='unexpected EOF while parsing'
-$B.raise_error_known_location(_b_.SyntaxError,filename,line_num,pos-line_start,line_num,pos-line_start+1,line,msg)}
+t.push(ErrorToken(_b_.SyntaxError,filename,line_num,pos-line_start,line_num,pos-line_start+1,line,msg))
+return t}
 line_num++
 pos+=mo[0].length
 line_start=pos+1
 line=get_line_at(pos)}else{pos++;
 var msg='unexpected character after line '+
 'continuation character'
-$B.raise_error_known_location(_b_.SyntaxError,filename,line_num,pos-line_start,line_num,pos-line_start+1,line,msg)}
+t.push(ErrorToken(_b_.SyntaxError,filename,line_num,pos-line_start,line_num,pos-line_start+1,line,msg))
+return t}
 break
 case '\n':
 case '\r':
 var token_name=braces.length > 0 ? 'NL':'NEWLINE'
 mo=/^\f?(\r\n|\r|\n)/.exec(src.substr(pos-1))
-yield Token(token_name,mo[0],line_num,pos-line_start,line_num,pos-line_start+mo[0].length,line)
+t.push(Token(token_name,mo[0],line_num,pos-line_start,line_num,pos-line_start+mo[0].length,line))
 pos+=mo[0].length-1
 if(token_name=='NEWLINE'){state='line_start'}else{line_num++
 line_start=pos+1
@@ -522,7 +533,7 @@ number=char}else if(ops.includes(char)){if(token_mode=='regular_within_fstring'
 if(nesting_level(token_modes)==braces.length-1){let colon=Token('OP',char,line_num,pos-line_start-op.length+1,line_num,pos-line_start+1,line)
 colon.metadata=src.substr(
 line_start+fstring_expr_start,pos-line_start-fstring_expr_start-1)
-yield colon
+t.push(colon)
 token_modes.pop()
 token_mode='format_specifier'
 token_modes.push(token_mode)
@@ -530,10 +541,11 @@ continue}}else{
 let closing_brace=Token('OP',char,line_num,pos-line_start-op.length+1,line_num,pos-line_start+1,line)
 closing_brace.metadata=src.substring(
 line_start+fstring_expr_start,pos-1)
-yield closing_brace
+t.push(closing_brace)
 token_modes.pop()
 token_mode=token_modes[token_modes.length-1]
-if(braces.length==0 ||$B.last(braces).char !=='{'){throw Error('wrong braces')}
+if(braces.length==0 ||$B.last(braces).char !=='{'){t.push(Error('wrong braces'))
+return t}
 braces.pop()
 continue}}
 var op=char
@@ -545,12 +557,12 @@ pos++}else if((char=='-' && src[pos]=='>')||
 (char==':' && src[pos]=='=')){op+=src[pos]
 pos++}
 if('[({'.includes(char)){braces.push({char,pos,line_num,line_start,line})}else if('])}'.includes(char)){if(braces.length && $last(braces).char==closing[char]){braces.pop()}else{braces.push({char,pos,line_num,line_start,line})}}
-yield Token('OP',op,line_num,pos-line_start-op.length+1,line_num,pos-line_start+1,line)}else if(char=='!'){if(src[pos]=='='){yield Token('OP','!=',line_num,pos-line_start,line_num,pos-line_start+2,line)
+t.push(Token('OP',op,line_num,pos-line_start-op.length+1,line_num,pos-line_start+1,line))}else if(char=='!'){if(src[pos]=='='){t.push(Token('OP','!=',line_num,pos-line_start,line_num,pos-line_start+2,line))
 pos++}else{
 let token=Token('OP',char,line_num,pos-line_start,line_num,pos-line_start+1,line)
 token.metadata=src.substring(
 line_start+fstring_start+2,pos-1)
-yield token}}else if(char==' ' ||char=='\t'){}else{
+t.push(token)}}else if(char==' ' ||char=='\t'){}else{
 var cp=char.codePointAt(0),err_msg='invalid'
 if(unprintable_re.exec(char)){err_msg+=' non-printable'}
 var unicode=cp.toString(16).toUpperCase()
@@ -558,7 +570,8 @@ while(unicode.length < 4){unicode='0'+unicode}
 err_msg+=` character '${char}' (U+${unicode})`
 if(char=='$' ||char=='`'){err_msg='invalid syntax'}
 var err_token=Token('ERRORTOKEN',char,line_num,pos-line_start,line_num,pos-line_start+1,line)
-$B.raise_error_known_token(_b_.SyntaxError,filename,err_token,err_msg)}}
+t.push(ErrorTokenKnownToken(_b_.SyntaxError,filename,err_token,err_msg))
+return t}}
 break
 case 'NAME':
 if($B.is_XID_Continue(ord(char))){name+=char}else if(char=='"' ||char=="'"){if(string_prefix.exec(name)||bytes_prefix.exec(name)){
@@ -576,13 +589,13 @@ token_mode.raw=prefix.toLowerCase().includes('r')
 token_modes.push(token_mode)
 var s=triple_quote ? quote.repeat(3):quote
 var end_col=fstring_start+name.length+s.length
-yield Token(FSTRING_START,prefix+s,line_num,fstring_start,line_num,end_col,line)
+t.push(Token(FSTRING_START,prefix+s,line_num,fstring_start,line_num,end_col,line))
 continue}
 escaped=false
 string_start=[line_num,pos-line_start-name.length,line_start]
-string=''}else{yield Token('NAME',name,line_num,pos-line_start-name.length,line_num,pos-line_start,line)
+string=''}else{t.push(Token('NAME',name,line_num,pos-line_start-name.length,line_num,pos-line_start,line))
 state=null
-pos--}}else{yield Token('NAME',name,line_num,pos-line_start-name.length,line_num,pos-line_start,line)
+pos--}}else{t.push(Token('NAME',name,line_num,pos-line_start-name.length,line_num,pos-line_start,line))
 state=null
 pos--}
 break
@@ -595,11 +608,11 @@ string_start[2]-1,pos+2)}
 var full_string
 if(! triple_quote){full_string=prefix+quote+string+
 quote
-yield Token('STRING',full_string,string_start[0],string_start[1],line_num,pos-line_start+1,string_line)
+t.push(Token('STRING',full_string,string_start[0],string_start[1],line_num,pos-line_start+1,string_line))
 state=null}else if(char+src.substr(pos,2)==
 quote.repeat(3)){full_string=prefix+quote.repeat(3)+
 string+quote.repeat(3)
-yield Token('STRING',full_string,string_start[0],string_start[1],line_num,pos-line_start+3,string_line)
+t.push(Token('STRING',full_string,string_start[0],string_start[1],line_num,pos-line_start+3,string_line))
 pos+=2
 state=null}else{string+=char}}else{string+=char}
 escaped=false
@@ -609,7 +622,8 @@ case '\n':
 if(! escaped && ! triple_quote){
 var msg=`unterminated string literal `+
 `(detected at line ${line_num})`,line_num=string_start[0],col_offset=string_start[1]
-$B.raise_error_known_location(_b_.SyntaxError,filename,line_num,col_offset,line_num,col_offset,line,msg)}
+t.push(ErrorToken(_b_.SyntaxError,filename,line_num,col_offset,line_num,col_offset,line,msg))
+return t}
 string+=char
 line_num++
 line_start=pos+1
@@ -631,17 +645,18 @@ break
 case 'NUMBER':
 if(test_num(num_type,char)){number+=char}else if(char=='_' && ! number.endsWith('.')){if(number.endsWith('_')){throw SyntaxError('consecutive _ in number')}else if(src[pos]===undefined ||
 ! test_num(num_type,src[pos])){
-yield Token('NUMBER',number,line_num,pos-line_start-number.length,line_num,pos-line_start,line)
+t.push(Token('NUMBER',number,line_num,pos-line_start-number.length,line_num,pos-line_start,line))
 state=null
 pos--}else{number+=char}}else if(char=='.' && ! number.includes(char)){number+=char}else if(char.toLowerCase()=='e' &&
 ! number.toLowerCase().includes('e')){if('+-'.includes(src[pos])||
-$B.in_unicode_category('Nd',ord(src[pos]))){number+=char}else{yield Token('NUMBER',number,line_num,pos-line_start-number.length,line_num,pos-line_start,line)
+$B.in_unicode_category('Nd',ord(src[pos]))){number+=char}else{t.push(Token('NUMBER',number,line_num,pos-line_start-number.length,line_num,pos-line_start,line))
 state=null
 pos--}}else if((char=='+' ||char=='-')&&
 number.toLowerCase().endsWith('e')){number+=char}else if(char.toLowerCase()=='j'){
 number+=char
-yield Token('NUMBER',number,line_num,pos-line_start-number.length+1,line_num,pos-line_start+1,line)
-state=null}else if(char.match(/\p{Letter}/u)){$B.raise_error_known_location(_b_.SyntaxError,filename,line_num,pos-line_start-number.length,line_num,pos-line_start,line,'invalid decimal literal')}else{yield Token('NUMBER',number,line_num,pos-line_start-number.length,line_num,pos-line_start,line)
+t.push(Token('NUMBER',number,line_num,pos-line_start-number.length+1,line_num,pos-line_start+1,line))
+state=null}else if(char.match(/\p{Letter}/u)){t.push(ErrorToken(_b_.SyntaxError,filename,line_num,pos-line_start-number.length,line_num,pos-line_start,line,'invalid decimal literal'))
+return t}else{t.push(Token('NUMBER',number,line_num,pos-line_start-number.length,line_num,pos-line_start,line))
 state=null
 pos--}
 break}}
@@ -649,22 +664,24 @@ switch(state){case 'line_start':
 line_num++
 break
 case 'NAME':
-yield Token('NAME',name,line_num,pos-line_start-name.length+1,line_num,pos-line_start+1,line)
+t.push(Token('NAME',name,line_num,pos-line_start-name.length+1,line_num,pos-line_start+1,line))
 break
 case 'NUMBER':
-yield Token('NUMBER',number,line_num,pos-line_start-number.length+1,line_num,pos-line_start+1,line)
+t.push(Token('NUMBER',number,line_num,pos-line_start-number.length+1,line_num,pos-line_start+1,line))
 break
 case 'STRING':
 line_num=string_start[0]
 line=lines[line_num-1]
 var msg=`unterminated ${triple_quote ? 'triple-quoted ' : ''}`+
 `string literal (detected at line ${line_num})`,col_offset=string_start[1]
-$B.raise_error_known_location(_b_.SyntaxError,filename,line_num,col_offset,line_num,col_offset,line,msg)}
-if(! src.endsWith('\n')&& state !=line_start){yield Token('NEWLINE','',line_num,pos-line_start+1,line_num,pos-line_start+1,line+'\n')
+t.push(ErrorToken(_b_.SyntaxError,filename,line_num,col_offset,line_num,col_offset,line,msg))
+return t}
+if(! src.endsWith('\n')&& state !=line_start){t.push(Token('NEWLINE','',line_num,pos-line_start+1,line_num,pos-line_start+1,line+'\n'))
 line_num++}
 while(indents.length > 0){indents.pop()
-yield Token('DEDENT','',line_num,0,line_num,0,'')}
-yield Token('ENDMARKER','',line_num,0,line_num,0,'')}})(__BRYTHON__)
+t.push(Token('DEDENT','',line_num,0,line_num,0,''))}
+t.push(Token('ENDMARKER','',line_num,0,line_num,0,''))
+return t}})(__BRYTHON__)
 ;
 (function($B){
 var binary_ops={'+':'Add','-':'Sub','*':'Mult','/':'Div','//':'FloorDiv','%':'Mod','**':'Pow','<<':'LShift','>>':'RShift','|':'BitOr','^':'BitXor','&':'BitAnd','@':'MatMult'}
@@ -14906,9 +14923,9 @@ throw exc}
 $B.raise_error_known_token=raise_error_known_token
 function set_position_from_EXTRA(ast_obj,EXTRA){for(var key in EXTRA){ast_obj[key]=EXTRA[key]}}
 var Parser=$B.Parser=function(src,filename,mode){
-var tokenizer=$B.tokenizer(src,filename,mode,this)
-this.tokenizer=tokenizer
-this.tok=tokenizer
+this._tokens=$B.tokenizer(src,filename,mode,this)
+this.pos=0
+this.tok={}
 this.mark=0
 this.fill=0
 this.level=0
@@ -14922,10 +14939,11 @@ this.mode=mode
 this.memo={}
 this.arena={a_objects:[]}
 if(filename){p.filename=filename}}
-var ignored=[$B.py_tokens.ENCODING,$B.py_tokens.NL,$B.py_tokens.COMMENT]
-Parser.prototype.read_token=function(){while(true){var next=this.tokenizer.next()
-if(! next.done){var value=next.value
-if(! ignored.includes(value.num_type)){this.tokens.push(value)
+Parser.prototype.read_token=function(){while(true){var next=this._tokens[this.pos++]
+if(next){var value=next
+if(! value.parser_ignored){
+if(value.$error_token){$B.raise_error_known_location(...value)}else if(value.$error_token_known_token){$B.raise_error_known_token(...value)}
+this.tokens[this.tokens.length]=value
 return value}}else{throw Error('tokenizer exhausted')}}}})(__BRYTHON__)
 ;
 (function($B){
@@ -15030,10 +15048,8 @@ while(type==TYPE_IGNORE){type=get_next_token(p,new_token);}
 if(p.start_rule==Py_single_input && type==ENDMARKER && p.parsing_started){type=NEWLINE;
 p.parsing_started=0;
 if(p.tok.indent && !(p.flags & PyPARSE_DONT_IMPLY_DEDENT)){p.tok.pendin=-p.tok.indent;
-p.tok.indent=0;}}
-else{
-p.parsing_started=1;}
-var t=p.tokens[p.fill];
+p.tok.indent=0;}}else{p.parsing_started=1;}
+var t=p.tokens[p.fill]
 return initialize_token(p,t,new_token,type);}
 $B._PyPegen.clear_memo_statistics=function(){for(let i=0;i < NSTATISTICS;i++){memo_statistics[i]=0;}}
 $B._PyPegen.get_memo_statistics=function(){var ret=new Array(NSTATISTICS);
@@ -15232,7 +15248,7 @@ function _is_end_of_source(p){var err=p.tok.done;
 return p.tokens[p.tokens.length-1].type=='ENDMARKER'}
 $B._PyPegen.tokenize_full_source_to_check_for_errors=function(p){var last_token=p.tokens[p.fill-1]
 var tokenizer=$B.tokenizer(p.src,p.filename,p.mode,p)
-for(var token of tokenizer){}
+p.tokens=p._tokens
 if(p.braces.length > 0){var brace=$B.last(p.braces),err_lineno,msg
 if('([{'.includes(brace.char)){err_lineno=brace.line_num}else{if(p.braces.length > 1){err_lineno=p.braces[p.braces.length-2].line_num}else{err_lineno=brace.line_num}}
 if(p.tokens.length==0 ||$B.last(p.tokens).lineno >=err_lineno){if('([{'.includes(brace.char)){msg=`'${brace.char}' was never closed`}else if(p.braces.length > 1){var closing=brace.char,opening=p.braces[p.braces.length-2].char
diff --git a/www/src/pegen.js b/www/src/pegen.js
index 452276c8b..c0dc09937 100644
--- a/www/src/pegen.js
+++ b/www/src/pegen.js
@@ -322,14 +322,12 @@ $B._PyPegen.fill_token = function(p){
             p.tok.pendin = -p.tok.indent;
             p.tok.indent = 0;
         }
-    }
-    else {
+    }else{
         p.parsing_started = 1;
     }
 
-    var t = p.tokens[p.fill];
+    var t = p.tokens[p.fill]
     return initialize_token(p, t, new_token, type);
-
 }
 
 /*
@@ -435,7 +433,7 @@ $B._PyPegen.expect_token = function(p, type){
         }
     }
     var t = p.tokens[p.mark];
-    if (t.num_type != type) {
+    if(t.num_type != type){
        return NULL;
     }
     p.mark += 1;
@@ -829,8 +827,7 @@ function _is_end_of_source(p) {
 $B._PyPegen.tokenize_full_source_to_check_for_errors = function(p){
     var last_token = p.tokens[p.fill - 1]
     var tokenizer = $B.tokenizer(p.src, p.filename, p.mode, p)
-    for(var token of tokenizer){
-    }
+    p.tokens = p._tokens
     if(p.braces.length > 0){
         var brace = $B.last(p.braces),
             err_lineno,
diff --git a/www/src/python_parser_peg_version.js b/www/src/python_parser_peg_version.js
index 33dce9399..a91644e87 100644
--- a/www/src/python_parser_peg_version.js
+++ b/www/src/python_parser_peg_version.js
@@ -167,7 +167,7 @@ var helper_functions = {
         get_last_token(p)
         $B._PyPegen.raise_error(p, errtype, msg, ...extra_args)
     },
-    
+
     RAISE_SYNTAX_ERROR: function(p, msg){
         var extra_args = []
         for(var i = 1, len = arguments.length; i < len; i++){
@@ -308,13 +308,11 @@ function set_position_from_EXTRA(ast_obj, EXTRA){
     }
 }
 
-
 var Parser = $B.Parser = function(src, filename, mode){
     // mode is 'file' for a script or exec(), 'eval' for eval()
-    // Normalize line ends
-    var tokenizer = $B.tokenizer(src, filename, mode, this)
-    this.tokenizer = tokenizer
-    this.tok = tokenizer
+    this._tokens = $B.tokenizer(src, filename, mode, this) // array
+    this.pos = 0
+    this.tok = {}
     this.mark = 0
     this.fill = 0
     this.level = 0
@@ -322,7 +320,7 @@ var Parser = $B.Parser = function(src, filename, mode){
     this.starting_lineno = 0;
     this.starting_col_offset = 0;
 
-    this.tokens = [] // generator_as_list(tokenizer)
+    this.tokens = []
     this.src = src
     this.filename = filename
     this.mode = mode
@@ -335,17 +333,18 @@ var Parser = $B.Parser = function(src, filename, mode){
     }
 }
 
-var ignored = [$B.py_tokens.ENCODING,
-    $B.py_tokens.NL,
-    $B.py_tokens.COMMENT]
-
 Parser.prototype.read_token = function(){
     while(true){
-        var next = this.tokenizer.next()
-        if(! next.done){
-            var value = next.value
-            if(! ignored.includes(value.num_type)){
-                this.tokens.push(value)
+        var next = this._tokens[this.pos++]
+        if(next){
+            var value = next
+            if(! value.parser_ignored){ // ENCODING, NL, COMMENT are ignored
+                if(value.$error_token){
+                    $B.raise_error_known_location(...value)
+                }else if(value.$error_token_known_token){
+                    $B.raise_error_known_token(...value)
+                }
+                this.tokens[this.tokens.length] = value
                 return value
             }
         }else{
diff --git a/www/src/python_tokenizer.js b/www/src/python_tokenizer.js
index dd3b51fde..ff14d2baa 100644
--- a/www/src/python_tokenizer.js
+++ b/www/src/python_tokenizer.js
@@ -152,6 +152,18 @@ var ops = '.,:;+-*/%~^|&=<>[](){}@', // ! is valid in f-strings
     augm_op = '+-*/%^|&=<>@',
     closing = {'}': '{', ']': '[', ')': '('}
 
+function ErrorToken(){
+    var args = Array.from(arguments)
+    args.$error_token = true
+    return args
+}
+
+function ErrorTokenKnownToken(){
+    var args = Array.from(arguments)
+    args.$error_token_known_token = true
+    return args
+}
+
 function Token(type, string, lineno, col_offset, end_lineno, end_col_offset,
         line){
     var res = {type, string, line, lineno, col_offset, end_lineno, end_col_offset}
@@ -159,7 +171,10 @@ function Token(type, string, lineno, col_offset, end_lineno, end_col_offset,
     if(type == 'OP'){
         res.num_type = $B.py_tokens[$B.EXACT_TOKEN_TYPES[string]]
     }else if(type == 'ENCODING'){
-        res.num_type = $B.py_tokens.ENCODING
+        //res.num_type = $B.py_tokens.ENCODING
+        res.parser_ignored = true
+    }else if(type == 'NL' || type == 'COMMENT'){
+        res.parser_ignored = true
     }
     res.bytes = res.string // cheating
     return res
@@ -256,9 +271,10 @@ function nesting_level(token_modes){
     }
 }
 
-$B.tokenizer = function*(src, filename, mode, parser){
+$B.tokenizer = function(src, filename, mode, parser){
     var string_prefix = /^(r|u|R|U|f|F|fr|Fr|fR|FR|rf|rF|Rf|RF)$/,
-        bytes_prefix = /^(b|B|br|Br|bR|BR|rb|rB|Rb|RB)$/
+        bytes_prefix = /^(b|B|br|Br|bR|BR|rb|rB|Rb|RB)$/,
+        t = []
 
     if(mode != 'eval' && ! src.endsWith('\n')){
         src += '\n'
@@ -313,7 +329,7 @@ $B.tokenizer = function*(src, filename, mode, parser){
         parser.braces = braces
     }
 
-    yield Token('ENCODING', 'utf-8', 0, 0, 0, 0, '')
+    t.push(Token('ENCODING', 'utf-8', 0, 0, 0, 0, ''))
 
     while(pos < src.length){
         char = src[pos]
@@ -354,13 +370,13 @@ $B.tokenizer = function*(src, filename, mode, parser){
                 }
                 if(fstring_buffer.length > 0){
                     // emit FSTRING_MIDDLE token
-                    yield Token(FSTRING_MIDDLE, fstring_buffer,
+                    t.push(Token(FSTRING_MIDDLE, fstring_buffer,
                         line_num, fstring_start,
                         line_num, fstring_start + fstring_buffer.length,
-                        line)
+                        line))
                 }
-                yield Token(FSTRING_END, char, line_num, pos - line_start,
-                            line_num, pos - line_start + 1, line)
+                t.push(Token(FSTRING_END, char, line_num, pos - line_start,
+                            line_num, pos - line_start + 1, line))
                 // pop from token modes
                 token_modes.pop()
                 token_mode = $B.last(token_modes)
@@ -375,10 +391,10 @@ $B.tokenizer = function*(src, filename, mode, parser){
                 }else{
                     // emit FSTRING_MIDDLE if not empty
                     if(fstring_buffer.length > 0){
-                        yield Token(FSTRING_MIDDLE, fstring_buffer,
+                        t.push(Token(FSTRING_MIDDLE, fstring_buffer,
                             line_num, fstring_start,
                             line_num, fstring_start + fstring_buffer.length,
-                            line)
+                            line))
                     }
                     token_mode = 'regular_within_fstring'
                     fstring_expr_start = pos - line_start
@@ -393,10 +409,10 @@ $B.tokenizer = function*(src, filename, mode, parser){
                     continue
                 }else{
                     // emit closing bracket token
-                    yield Token('OP', char,
+                    t.push(Token('OP', char,
                         line_num, pos - line_start,
                         line_num, pos - line_start + 1,
-                        line)
+                        line))
                     continue
                 }
             }else if(char == '\\'){
@@ -424,10 +440,10 @@ $B.tokenizer = function*(src, filename, mode, parser){
             if(char == quote){
                 if(format_specifier.length > 0){
                     // emit FSTRING_MIDDLE token
-                    yield Token(FSTRING_MIDDLE, format_specifier,
+                    t.push(Token(FSTRING_MIDDLE, format_specifier,
                         line_num, fstring_start,
                         line_num, fstring_start + format_specifier.length,
-                        line)
+                        line))
                     // pop from token modes
                     token_modes.pop()
                     token_mode = $B.last(token_modes)
@@ -435,25 +451,25 @@ $B.tokenizer = function*(src, filename, mode, parser){
                 }
             }else if(char == '{'){
                 // emit FSTRING_MIDDLE
-                yield Token(FSTRING_MIDDLE, format_specifier,
+                t.push(Token(FSTRING_MIDDLE, format_specifier,
                     line_num, fstring_start,
                     line_num, fstring_start + format_specifier.length,
-                    line)
+                    line))
                 token_mode = 'regular_within_fstring'
                 fstring_expr_start = pos - line_start
                 state = null
                 token_modes.push(token_mode)
             }else if(char == '}'){
                 // emit FSTRING_MIDDLE
-                yield Token(FSTRING_MIDDLE, format_specifier,
+                t.push(Token(FSTRING_MIDDLE, format_specifier,
                     line_num, fstring_start,
                     line_num, fstring_start + format_specifier.length,
-                    line)
+                    line))
                 // emit closing bracket token
-                yield Token('OP', char,
+                t.push(Token('OP', char,
                     line_num, pos - line_start,
                     line_num, pos - line_start + 1,
-                    line)
+                    line))
                 if(braces.length == 0 || $B.last(braces).char !== '{'){
                     throw Error('wrong braces')
                 }
@@ -476,16 +492,16 @@ $B.tokenizer = function*(src, filename, mode, parser){
                 line_num++
                 if(mo = /^\f?(\r\n|\r|\n)/.exec(src.substr(pos - 1))){
                     // line break
-                    yield Token('NL', mo[0], line_num, 0,
+                    t.push(Token('NL', mo[0], line_num, 0,
                         line_num, mo[0].length,
-                        line)
+                        line))
                     pos += mo[0].length - 1
                     continue
                 }else if(char == '#'){
                     comment = get_comment(parser, src, pos, line_num,
                         line_start, 'NL', line)
                     for(var item of comment.t){
-                        yield item
+                        t.push(item)
                     }
                     pos = comment.pos
                     state = 'line_start'
@@ -502,15 +518,14 @@ $B.tokenizer = function*(src, filename, mode, parser){
                     var broken = false
                     while(pos < src.length){
                         if(broken && indent > 0 && ' \t'.includes(src[pos])){
-                            console.log('indentation error 479')
-                            $B.raise_error_known_location(
+                            t.push(ErrorToken(
                                 _b_.IndentationError,
                                 filename,
                                 line_num, pos - line_start,
                                 line_num, pos - line_start + 1,
                                 line,
-                                'unindent does not match any outer indentation level'
-                            )
+                                'unindent does not match any outer indentation level'))
+                            return t
                         }
                         if(src[pos] == ' '){
                             indent++
@@ -539,7 +554,7 @@ $B.tokenizer = function*(src, filename, mode, parser){
                         comment = get_comment(parser, src, pos + 1, line_num,
                             line_start, 'NL', line)
                         for(var item of comment.t){
-                            yield item
+                            t.push(item)
                         }
                         pos = comment.pos
                         continue
@@ -549,36 +564,38 @@ $B.tokenizer = function*(src, filename, mode, parser){
                             pos++
                             continue
                         }else{
-                            $B.raise_error_known_location(_b_.SyntaxError,
+                            t.push(ErrorToken(_b_.SyntaxError,
                                 filename, line_num, pos + 2 - line_start,
                                 line_num, pos + 3 - line_start,
                                 line,
-                                'unexpected character after line continuation character')
+                                'unexpected character after line continuation character'))
+                            return t
                         }
                     }else if(mo = /^\f?(\r\n|\r|\n)/.exec(src.substr(pos))){
                         // whitespace-only line
-                        yield Token('NL', '', line_num, pos - line_start + 1,
-                          line_num, pos - line_start + 1 + mo[0].length, line)
+                        t.push(Token('NL', '', line_num, pos - line_start + 1,
+                          line_num, pos - line_start + 1 + mo[0].length, line))
                         pos += mo[0].length
                         continue
                     }
                     if(indents.length == 0 || indent > $last(indents)){
                         indents.push(indent)
-                        yield Token('INDENT', '', line_num, 0,
-                            line_num, indent, line)
+                        t.push(Token('INDENT', '', line_num, 0,
+                            line_num, indent, line))
                     }else if(indent < $last(indents)){
                         var ix = indents.indexOf(indent)
                         if(ix == -1){
                             var message = 'unindent does not match ' +
                                 'any outer indentation level'
-                            $B.raise_error_known_location(_b_.IndentationError,
+                            t.push(ErrorToken(_b_.IndentationError,
                                 filename, line_num, 0,
-                                line_num, 0, line, message)
+                                line_num, 0, line, message))
+                            return t
                         }
                         for(var i = indents.length - 1; i > ix; i--){
                             indents.pop()
-                            yield Token('DEDENT', '', line_num, indent,
-                                line_num, indent, line)
+                            t.push(Token('DEDENT', '', line_num, indent,
+                                line_num, indent, line))
                         }
                     }
                     state = null
@@ -586,8 +603,8 @@ $B.tokenizer = function*(src, filename, mode, parser){
                     // dedent all
                     while(indents.length > 0){
                         indents.pop()
-                        yield Token('DEDENT', '', line_num, indent,
-                          line_num, indent, line)
+                        t.push(Token('DEDENT', '', line_num, indent,
+                          line_num, indent, line))
                     }
                     state = null
                     pos--
@@ -614,7 +631,7 @@ $B.tokenizer = function*(src, filename, mode, parser){
                         comment = get_comment(parser, src, pos, line_num, line_start,
                             token_name, line)
                         for(var item of comment.t){
-                            yield item
+                            t.push(item)
                         }
                         pos = comment.pos
                         if(braces.length == 0){
@@ -650,11 +667,12 @@ $B.tokenizer = function*(src, filename, mode, parser){
                                     let msg = 'leading zeros in decimal integer ' +
                                         'literals are not permitted; use an 0o prefix ' +
                                         'for octal integers'
-                                    $B.raise_error_known_location(_b_.SyntaxError,
+                                    t.push(ErrorToken(_b_.SyntaxError,
                                         filename,
                                         line_num, pos - line_start - number.length,
                                         line_num, pos - line_start,
-                                        line, msg)
+                                        line, msg))
+                                    return t
                                 }else{
                                     break
                                 }
@@ -676,13 +694,13 @@ $B.tokenizer = function*(src, filename, mode, parser){
                             while(op.length >= 3){
                                 // sequences of 3 consecutive dots are sent
                                 // as a single token for Ellipsis
-                                yield Token('OP', '...', line_num, dot_pos,
-                                    line_num, dot_pos + 3, line)
+                                t.push(Token('OP', '...', line_num, dot_pos,
+                                    line_num, dot_pos + 3, line))
                                 op = op.substr(3)
                             }
                             for(var i = 0; i < op.length; i++){
-                                yield Token('OP', '.', line_num, dot_pos,
-                                    line_num, dot_pos + 1, line)
+                                t.push(Token('OP', '.', line_num, dot_pos,
+                                    line_num, dot_pos + 1, line))
                                 dot_pos++
                             }
                         }
@@ -692,9 +710,10 @@ $B.tokenizer = function*(src, filename, mode, parser){
                         if(mo){
                             if(pos == src.length - 1){
                                 var msg = 'unexpected EOF while parsing'
-                                $B.raise_error_known_location(_b_.SyntaxError,
+                                t.push(ErrorToken(_b_.SyntaxError,
                                     filename, line_num, pos - line_start, line_num, pos - line_start + 1,
-                                    line, msg)
+                                    line, msg))
+                                return t
                             }
                             line_num++
                             pos += mo[0].length
@@ -704,18 +723,19 @@ $B.tokenizer = function*(src, filename, mode, parser){
                             pos++;
                             var msg = 'unexpected character after line ' +
                                 'continuation character'
-                            $B.raise_error_known_location(_b_.SyntaxError,
+                            t.push(ErrorToken(_b_.SyntaxError,
                                 filename, line_num, pos - line_start, line_num, pos - line_start + 1,
-                                line, msg)
+                                line, msg))
+                            return t
                         }
                         break
                     case '\n':
                     case '\r':
                         var token_name = braces.length > 0 ? 'NL': 'NEWLINE'
                         mo = /^\f?(\r\n|\r|\n)/.exec(src.substr(pos - 1))
-                        yield Token(token_name, mo[0],
+                        t.push(Token(token_name, mo[0],
                             line_num, pos - line_start,
-                            line_num, pos - line_start + mo[0].length, line)
+                            line_num, pos - line_start + mo[0].length, line))
                         pos += mo[0].length - 1
                         if(token_name == 'NEWLINE'){
                             state = 'line_start'
@@ -751,7 +771,7 @@ $B.tokenizer = function*(src, filename, mode, parser){
                                         colon.metadata = src.substr(
                                             line_start + fstring_expr_start,
                                             pos - line_start - fstring_expr_start - 1)
-                                        yield colon
+                                        t.push(colon)
                                         token_modes.pop()
                                         token_mode = 'format_specifier'
                                         token_modes.push(token_mode)
@@ -765,11 +785,12 @@ $B.tokenizer = function*(src, filename, mode, parser){
                                         line)
                                     closing_brace.metadata = src.substring(
                                         line_start + fstring_expr_start, pos - 1)
-                                    yield closing_brace
+                                    t.push(closing_brace)
                                     token_modes.pop()
                                     token_mode = token_modes[token_modes.length - 1]
                                     if(braces.length == 0 || $B.last(braces).char !== '{'){
-                                        throw Error('wrong braces')
+                                        t.push(Error('wrong braces'))
+                                        return t
                                     }
                                     braces.pop()
                                     continue
@@ -798,16 +819,16 @@ $B.tokenizer = function*(src, filename, mode, parser){
                                     braces.push({char, pos, line_num, line_start, line})
                                 }
                             }
-                            yield Token('OP', op,
+                            t.push(Token('OP', op,
                                 line_num, pos - line_start - op.length + 1,
                                 line_num, pos - line_start + 1,
-                                line)
+                                line))
                         }else if(char == '!'){
                             if(src[pos] == '='){
-                                yield Token('OP', '!=',
+                                t.push(Token('OP', '!=',
                                     line_num, pos - line_start,
                                     line_num, pos - line_start + 2,
-                                    line)
+                                    line))
                                 pos++
                             }else{
                                 // conversion
@@ -818,7 +839,7 @@ $B.tokenizer = function*(src, filename, mode, parser){
                                 // used on fstring debug mode
                                 token.metadata = src.substring(
                                     line_start + fstring_start + 2, pos - 1)
-                                yield token
+                                t.push(token)
                             }
                         }else if(char == ' ' || char == '\t'){
                             // ignore
@@ -841,8 +862,9 @@ $B.tokenizer = function*(src, filename, mode, parser){
                                 line_num, pos - line_start,
                                 line_num, pos - line_start + 1,
                                 line)
-                            $B.raise_error_known_token(_b_.SyntaxError, filename,
-                                err_token, err_msg)
+                            t.push(ErrorTokenKnownToken(_b_.SyntaxError, filename,
+                                err_token, err_msg))
+                            return t
                         }
               }
               break
@@ -870,10 +892,10 @@ $B.tokenizer = function*(src, filename, mode, parser){
                             token_modes.push(token_mode)
                             var s = triple_quote ? quote.repeat(3) : quote
                             var end_col = fstring_start + name.length + s.length
-                            yield Token(FSTRING_START, prefix + s,
+                            t.push(Token(FSTRING_START, prefix + s,
                                 line_num, fstring_start,
                                 line_num, end_col,
-                                line)
+                                line))
                             continue
                         }
                         escaped = false
@@ -881,18 +903,18 @@ $B.tokenizer = function*(src, filename, mode, parser){
                             pos - line_start - name.length, line_start]
                         string = ''
                     }else{
-                        yield Token('NAME', name,
+                        t.push(Token('NAME', name,
                             line_num, pos - line_start - name.length,
                             line_num, pos - line_start,
-                            line)
+                            line))
                         state = null
                         pos--
                     }
                 }else{
-                    yield Token('NAME', name,
+                    t.push(Token('NAME', name,
                         line_num, pos - line_start - name.length,
                         line_num, pos - line_start,
-                        line)
+                        line))
                     state = null
                     pos--
                 }
@@ -914,10 +936,10 @@ $B.tokenizer = function*(src, filename, mode, parser){
                             if(! triple_quote){
                                 full_string = prefix + quote + string +
                                   quote
-                                yield Token('STRING', full_string,
+                                t.push(Token('STRING', full_string,
                                     string_start[0], string_start[1],
                                     line_num, pos - line_start + 1,
-                                    string_line)
+                                    string_line))
                                 state = null
                             }else if(char + src.substr(pos, 2) ==
                                     quote.repeat(3)){
@@ -926,10 +948,10 @@ $B.tokenizer = function*(src, filename, mode, parser){
                                 // For triple-quoted strings, if it spans over
                                 // several lines, "line" is extended until the
                                 // last quote
-                                yield Token('STRING', full_string,
+                                t.push(Token('STRING', full_string,
                                     string_start[0], string_start[1],
                                     line_num, pos - line_start + 3,
-                                    string_line)
+                                    string_line))
                                 pos += 2
                                 state = null
                             }else{
@@ -948,11 +970,12 @@ $B.tokenizer = function*(src, filename, mode, parser){
                                       `(detected at line ${line_num})`,
                                 line_num = string_start[0],
                                 col_offset = string_start[1]
-                            $B.raise_error_known_location(_b_.SyntaxError,
+                            t.push(ErrorToken(_b_.SyntaxError,
                                 filename, line_num, col_offset,
                                 line_num, col_offset,
                                 line,
-                                msg)
+                                msg))
+                            return t
                         }
                         string += char
                         line_num++
@@ -985,10 +1008,10 @@ $B.tokenizer = function*(src, filename, mode, parser){
                     }else if(src[pos] === undefined ||
                             ! test_num(num_type, src[pos])){
                         // eg 12_
-                        yield Token('NUMBER', number,
+                        t.push(Token('NUMBER', number,
                             line_num, pos - line_start - number.length,
                             line_num, pos - line_start,
-                            line)
+                            line))
                         state = null
                         pos--
                     }else{
@@ -1002,10 +1025,10 @@ $B.tokenizer = function*(src, filename, mode, parser){
                             $B.in_unicode_category('Nd', ord(src[pos]))){
                         number += char
                     }else{
-                        yield Token('NUMBER', number,
+                        t.push(Token('NUMBER', number,
                             line_num, pos - line_start - number.length,
                             line_num, pos - line_start,
-                            line)
+                            line))
                         state = null
                         pos--
                     }
@@ -1014,22 +1037,23 @@ $B.tokenizer = function*(src, filename, mode, parser){
                     number += char
                 }else if(char.toLowerCase() == 'j'){ // complex number
                     number += char
-                    yield Token('NUMBER', number,
+                    t.push(Token('NUMBER', number,
                         line_num, pos - line_start - number.length + 1,
                         line_num, pos - line_start + 1,
-                        line)
+                        line))
                     state = null
                 }else if(char.match(/\p{Letter}/u)){
-                    $B.raise_error_known_location(_b_.SyntaxError,
+                    t.push(ErrorToken(_b_.SyntaxError,
                         filename,
                         line_num, pos - line_start - number.length,
                         line_num, pos - line_start,
-                        line, 'invalid decimal literal')
+                        line, 'invalid decimal literal'))
+                    return t
                 }else{
-                    yield Token('NUMBER', number,
+                    t.push(Token('NUMBER', number,
                         line_num, pos - line_start - number.length,
                         line_num, pos - line_start,
-                        line)
+                        line))
                     state = null
                     pos--
                 }
@@ -1042,17 +1066,17 @@ $B.tokenizer = function*(src, filename, mode, parser){
             line_num++
             break
         case 'NAME':
-            yield Token('NAME', name,
+            t.push(Token('NAME', name,
                 line_num, pos - line_start - name.length + 1,
                 line_num, pos - line_start + 1,
-                line)
+                line))
 
             break
         case 'NUMBER':
-            yield Token('NUMBER', number,
+            t.push(Token('NUMBER', number,
               line_num, pos - line_start - number.length + 1,
               line_num, pos - line_start + 1,
-              line)
+              line))
             break
         case 'STRING':
             line_num = string_start[0]
@@ -1060,24 +1084,27 @@ $B.tokenizer = function*(src, filename, mode, parser){
             var msg = `unterminated ${triple_quote ? 'triple-quoted ' : ''}` +
                 `string literal (detected at line ${line_num})`,
                 col_offset = string_start[1]
-            $B.raise_error_known_location(_b_.SyntaxError,
+            t.push(ErrorToken(_b_.SyntaxError,
                 filename, line_num, col_offset,
                 line_num, col_offset,
                 line,
-                msg)
+                msg))
+            return t
 }
 
     if(! src.endsWith('\n') && state != line_start){
-        yield Token('NEWLINE', '', line_num, pos - line_start + 1,
-            line_num, pos - line_start + 1, line +'\n')
+        t.push(Token('NEWLINE', '', line_num, pos - line_start + 1,
+            line_num, pos - line_start + 1, line +'\n'))
         line_num++
     }
 
     while(indents.length > 0){
         indents.pop()
-        yield Token('DEDENT', '', line_num, 0, line_num, 0, '')
+        t.push(Token('DEDENT', '', line_num, 0, line_num, 0, ''))
     }
-    yield Token('ENDMARKER', '', line_num, 0, line_num, 0, '')
+    t.push(Token('ENDMARKER', '', line_num, 0, line_num, 0, ''))
+
+    return t
 
 }
 })(__BRYTHON__)
diff --git a/www/src/version_info.js b/www/src/version_info.js
index 261e05b6e..2db200cc6 100644
--- a/www/src/version_info.js
+++ b/www/src/version_info.js
@@ -1,7 +1,7 @@
 __BRYTHON__.implementation = [3, 13, 1, 'dev', 0]
 __BRYTHON__.version_info = [3, 13, 0, 'final', 0]
-__BRYTHON__.compiled_date = "2024-11-05 10:25:30.265416"
-__BRYTHON__.timestamp = 1730798730264
+__BRYTHON__.compiled_date = "2024-11-05 13:35:50.668375"
+__BRYTHON__.timestamp = 1730810150668
 __BRYTHON__.builtin_module_names = ["_ajax",
     "_ast",
     "_base64",