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test.js
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test.js
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function parseABNF(input) {
const ruleDefinitions = {};
function parseRule() {
const ruleName = parseToken();
parseChar('=');
const ruleDefinition = parseElements();
parseChar(';');
ruleDefinitions[ruleName] = ruleDefinition;
}
function parseElements() {
const elements = [];
while (true) {
const element = parseAlternation();
elements.push(element);
if (parseChar('/')) {
continue;
} else {
break;
}
}
return elements;
}
function parseAlternation() {
const alternation = [];
while (true) {
const concatenation = parseConcatenation();
alternation.push(concatenation);
if (parseChar('|')) {
continue;
} else {
break;
}
}
return alternation;
}
function parseConcatenation() {
const concatenation = [];
while (true) {
const repetition = parseRepetition();
concatenation.push(repetition);
if (repetition === null || repetition === ')' || repetition === ']') {
break;
}
}
return concatenation;
}
function parseRepetition() {
const repetition = [];
const element = parseElement();
repetition.push(element);
if (parseChar('*')) {
repetition.push('*');
} else if (parseChar('+')) {
repetition.push('+');
} else if (parseChar('?')) {
repetition.push('?');
}
return repetition.length > 1 ? repetition : element;
}
function parseElement() {
if (parseChar('"')) {
const literal = parseLiteral();
parseChar('"');
return literal;
} else if (parseChar('(')) {
const alternation = parseAlternation();
parseChar(')');
return alternation;
} else if (parseChar('[')) {
const option = parseOption();
parseChar(']');
return option;
} else {
return parseToken();
}
}
function parseOption() {
const option = [];
while (true) {
const alternation = parseAlternation();
option.push(alternation);
if (alternation[0] === ')' || alternation[0] === ']') {
break;
}
}
return option;
}
function parseLiteral() {
let literal = '';
while (true) {
const char = input[0];
if (char === '"') {
break;
} else if (char === '\\') {
literal += input[1];
input = input.slice(2);
} else {
literal += char;
input = input.slice(1);
}
}
return literal;
}
function parseToken() {
let token = '';
while (true) {
const char = input[0];
if (char === ' ' || char === '\t' || char === '\n') {
break;
} else if (char === ':') {
input = input.slice(1);
break;
} else {
token += char;
input = input.slice(1);
}
}
return token;
}
function parseChar(expectedChar) {
if (input[0] === expectedChar) {
input = input.slice(1);
return expectedChar;
}
return null;
}
// Remove leading and trailing whitespace
input = input.trim();
while (input.length > 0) {
parseRule();
}
return ruleDefinitions;
}
// Example ABNF grammar
const abnfGrammar = `
DIGIT = "0" / "1" / "2" / "3" / "4" / "5" / "6" / "7" / "8" / "9"
ALPHA = %x41-5A / %x61-7A
HEXDIG = DIGIT / "A" / "B" / "C" / "D" / "E" / "F"
OCTET = DIGIT / %x31-39 DIGIT / "1" 2DIGIT / "2" %x30-34 DIGIT / "25" %x30-35
CIDR = DIGIT / %x31-32 DIGIT / "3" %x30-32
`;
// Parse the ABNF grammar
const result = parseABNF(abnfGrammar);
console.log('Parsing successful!');
console.log('Result:', result);