extend isbound() to checking for undefined array and struct elements

closes #105

base/deepcopy.jl

@@ -31,13 +31,8 @@ function _deepcopy_t(x, T::CompositeKind, stackdict::ObjectIdDict)
     ret = ccall(:jl_new_struct_uninit, Any, (Any,), T)
     stackdict[x] = ret
     for f in T.names
-        try
+        if isbound(x,f)
             ret.(f) = deepcopy_internal(x.(f), stackdict)
-        catch err
-            # we ignore undefined references errors
-            if !isa(err, UndefRefError)
-                throw(err)
-            end
         end
     end
     return ret
@@ -57,19 +52,9 @@ _deepcopy_array_t(x, T::BitsKind, stackdict::ObjectIdDict) = copy(x)
 function _deepcopy_array_t(x, T, stackdict::ObjectIdDict)
     dest = similar(x)
     stackdict[x] = dest
-    i0 = 1; local i
-    while true
-        try
-            for i=i0:length(x)
-                arrayset(dest, deepcopy_internal(x[i], stackdict), i)
-            end
-            break
-        catch err
-            # we ignore undefined references errors
-            if !isa(err, UndefRefError)
-                throw(err)
-            end
-            i0 = i+1
+    for i=1:length(x)
+        if isbound(x,i)
+            arrayset(dest, deepcopy_internal(x[i], stackdict), i)
         end
     end
     return dest

base/show.jl

@@ -568,11 +568,10 @@ function alignment(
     for j in cols
         l = r = 0
         for i in rows
-            aij = _jl_undef_ref_alignment
-            try
+            if isbound(X,i,j)
                 aij = alignment(X[i,j])
-            catch err
-                if !isa(err,UndefRefError) throw(err) end
+            else
+                aij = _jl_undef_ref_alignment
             end
             l = max(l, aij[1])
             r = max(r, aij[2])
@@ -597,14 +596,13 @@ function print_matrix_row(io,
 )
     for k = 1:length(A)
         j = cols[k]
-        a = _jl_undef_ref_alignment
-        sx = _jl_undef_ref_str
-        try
+        if isbound(X,i,j)
             x = X[i,j]
             a = alignment(x)
             sx = sprint(showcompact, x)
-        catch err
-            if !isa(err,UndefRefError) throw(err) end
+        else
+            a = _jl_undef_ref_alignment
+            sx = _jl_undef_ref_str
         end
         l = repeat(" ", A[k][1]-a[1])
         r = repeat(" ", A[k][2]-a[2])
@@ -768,11 +766,10 @@ whos(pat::Regex) = whos(ccall(:jl_get_current_module, Module, ()), pat)
 
 function show{T}(io, x::AbstractArray{T,0})
     println(io, summary(x),":")
-    sx = _jl_undef_ref_str
-    try
+    if isbound(x)
         sx = sprint(showcompact, x[])
-    catch err
-        if !isa(err,UndefRefError) throw(err) end
+    else
+        sx = _jl_undef_ref_str
     end
     print(io, sx)
 end

src/alloc.c

@@ -151,6 +151,18 @@ jl_value_t *jl_get_nth_field(jl_value_t *v, size_t i)
                        (char*)v + offs);
 }
 
+int jl_field_isassigned(jl_value_t *v, jl_sym_t *fld, int err)
+{
+    jl_struct_type_t *st = (jl_struct_type_t*)jl_typeof(v);
+    int i = jl_field_index(st, fld, err);
+    if (i == -1) return 0;
+    size_t offs = jl_field_offset(st,i) + sizeof(void*);
+    if (st->fields[i].isptr) {
+        return *(jl_value_t**)((char*)v + offs) != NULL;
+    }
+    return 1;
+}
+
 jl_value_t *jl_set_nth_field(jl_value_t *v, size_t i, jl_value_t *rhs)
 {
     jl_struct_type_t *st = (jl_struct_type_t*)jl_typeof(v);

src/array.c

@@ -410,6 +410,16 @@ JL_CALLABLE(jl_f_arrayref)
     return jl_arrayref(a, i);
 }
 
+int jl_array_isassigned(jl_value_t **args, int nargs)
+{
+    assert(jl_is_array(args[0]));
+    jl_array_t *a = (jl_array_t*)args[0];
+    size_t i = array_nd_index(a, &args[1], nargs-1, "isbound");
+    if (a->ptrarray)
+        return ((jl_value_t**)jl_array_data(a))[i] != NULL;
+    return 1;
+}
+
 void jl_arrayset(jl_array_t *a, jl_value_t *rhs, size_t i)
 {
     jl_value_t *el_type = jl_tparam0(jl_typeof(a));

src/builtins.c

@@ -308,6 +308,10 @@ JL_CALLABLE(jl_f_isbound)
 {
     jl_module_t *m = jl_current_module;
     jl_sym_t *s=NULL;
+    JL_NARGSV(isbound, 1);
+    if (jl_is_array(args[0])) {
+        return jl_array_isassigned(args, nargs) ? jl_true : jl_false;
+    }
     if (nargs == 1) {
         JL_TYPECHK(isbound, symbol, args[0]);
         s = (jl_sym_t*)args[0];
@@ -316,10 +320,17 @@ JL_CALLABLE(jl_f_isbound)
         JL_NARGS(isbound, 1, 1);
     }
     else {
-        JL_TYPECHK(isbound, module, args[0]);
         JL_TYPECHK(isbound, symbol, args[1]);
-        m = (jl_module_t*)args[0];
         s = (jl_sym_t*)args[1];
+        if (!jl_is_module(args[0])) {
+            jl_value_t *vt = (jl_value_t*)jl_typeof(args[0]);
+            if (!jl_is_struct_type(vt)) {
+                jl_type_error("isbound", (jl_value_t*)jl_struct_kind, args[0]);
+            }
+            return jl_field_isassigned(args[0], s, 1) ? jl_true : jl_false;
+        }
+        JL_TYPECHK(isbound, module, args[0]);
+        m = (jl_module_t*)args[0];
     }
     assert(s);
     return jl_boundp(m, s) ? jl_true : jl_false;

src/julia.h

@@ -717,6 +717,7 @@ void jl_compute_struct_offsets(jl_struct_type_t *st);
 int jl_field_index(jl_struct_type_t *t, jl_sym_t *fld, int err);
 DLLEXPORT jl_value_t *jl_get_nth_field(jl_value_t *v, size_t i);
 jl_value_t *jl_set_nth_field(jl_value_t *v, size_t i, jl_value_t *rhs);
+int jl_field_isassigned(jl_value_t *v, jl_sym_t *fld, int err);
 
 // arrays
 DLLEXPORT jl_array_t *jl_new_array(jl_type_t *atype, jl_tuple_t *dims);
@@ -740,6 +741,7 @@ DLLEXPORT jl_value_t *jl_array_to_string(jl_array_t *a);
 DLLEXPORT jl_array_t *jl_alloc_cell_1d(size_t n);
 DLLEXPORT jl_value_t *jl_arrayref(jl_array_t *a, size_t i);  // 0-indexed
 DLLEXPORT void jl_arrayset(jl_array_t *a, jl_value_t *v, size_t i);  // 0-indexed
+int jl_array_isassigned(jl_value_t **args, int nargs);
 DLLEXPORT void *jl_array_ptr(jl_array_t *a);
 DLLEXPORT void jl_array_grow_end(jl_array_t *a, size_t inc);
 DLLEXPORT void jl_array_del_end(jl_array_t *a, size_t dec);

test/core.jl

@@ -242,6 +242,33 @@ glotest()
 # syntax
 @assert (true ? 1 : false ? 2 : 3) == 1
 
+type UndefField
+    field
+    UndefField() = new()
+end
+
+# undefinedness
+begin
+    local a
+    a = cell(2)
+    @assert !isbound(a,1) && !isbound(a,2)
+    a[1] = 1
+    @assert isbound(a,1) && !isbound(a,2)
+    a = Array(Float64,1)
+    @assert isbound(a,1)
+    @assert isbound(a)
+    @assert_fails isbound(a,2)
+
+    @assert isbound("a",:data)
+    a = UndefField()
+    @assert !isbound(a, :field)
+    @assert_fails isbound(a, :foo)
+
+    @assert_fails isbound(2)
+    @assert_fails isbound(2, :a)
+    @assert_fails isbound("a", 2)
+end
+
 # dispatch
 begin
     local foo, bar, baz