bool
ASTNode::check_arglist (const char *funcname, ASTNode::ref arg,
const char *formals, bool coerce)
{
// std::cerr << "ca " << funcname << " formals='" << formals << "\n";
for ( ; arg; arg = arg->next()) {
if (! *formals) // More formal args, but no more actual args
return false;
if (*formals == '*') // Will match anything left
return true;
if (*formals == '.') { // Special case for token/value pairs
// FIXME -- require that the tokens be string literals
if (arg->typespec().is_string() && arg->next() != NULL) {
arg = arg->next();
continue;
}
return false;
}
if (*formals == '?') {
if (formals[1] == '[' && formals[2] == ']') {
// Any array
formals += 3;
if (arg->typespec().is_array())
continue; // match
else return false; // wanted an array, didn't get one
}
if (arg->typespec().is_array())
return false; // wanted any scalar, got an array
formals += 1;
continue; // match anything
}
TypeSpec argtype = arg->typespec();
int advance;
TypeSpec formaltype = m_compiler->type_from_code (formals, &advance);
formals += advance;
// std::cerr << "\targ is " << argtype.string()
// << ", formal is " << formaltype.string() << "\n";
if (argtype == formaltype)
continue; // ok, move on to next arg
if (coerce && assignable (formaltype, argtype))
continue;
// Allow a fixed-length array match to a formal array with
// unspecified length, if the element types are the same.
if (formaltype.arraylength() < 0 && argtype.arraylength() &&
formaltype.elementtype() == argtype.elementtype())
continue;
// anything that gets this far we don't consider a match
return false;
}
if (*formals && *formals != '*' && *formals != '.')
return false; // Non-*, non-... formals expected, no more actuals
return true; // Is this safe?
}
TypeSpec
ASTfunction_call::typecheck (TypeSpec expected)
{
typecheck_children ();
bool match = false;
// Look for an exact match, including expected return type
m_typespec = typecheck_all_poly (expected, false);
if (m_typespec != TypeSpec())
match = true;
// Now look for an exact match on args, but any assignable return type
if (! match && expected != TypeSpec()) {
m_typespec = typecheck_all_poly (TypeSpec(), false);
if (m_typespec != TypeSpec())
match = true;
}
// Now look for a coercible match of args, exact march on return type
if (! match) {
m_typespec = typecheck_all_poly (expected, true);
if (m_typespec != TypeSpec())
match = true;
}
// All that failed, try for a coercible match on everything
if (! match && expected != TypeSpec()) {
m_typespec = typecheck_all_poly (TypeSpec(), true);
if (m_typespec != TypeSpec())
match = true;
}
if (match) {
if (! is_user_function ())
typecheck_builtin_specialcase ();
return m_typespec;
}
// Couldn't find any way to match any polymorphic version of the
// function that we know about. OK, at least try for helpful error
// message.
std::string choices ("");
for (FunctionSymbol *poly = func(); poly; poly = poly->nextpoly()) {
const char *code = poly->argcodes().c_str();
int advance;
TypeSpec returntype = m_compiler->type_from_code (code, &advance);
code += advance;
if (choices.length())
choices += "\n";
choices += Strutil::format ("\t%s %s (%s)",
type_c_str(returntype), m_name.c_str(),
m_compiler->typelist_from_code(code).c_str());
}
std::string actualargs;
for (ASTNode::ref arg = args(); arg; arg = arg->next()) {
if (actualargs.length())
actualargs += ", ";
actualargs += arg->typespec().string();
}
error ("No matching function call to '%s (%s)'\n Candidates are:\n%s",
m_name.c_str(), actualargs.c_str(), choices.c_str());
return TypeSpec();
}