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#include "parser.ih"
// Only with %type a symbol may already exist.
//
// Symbols are defined by %token, %left etc. as terminals only.
//
// At a %type declaration, their types can be set, but only if their types
// haven't been set yet.
//
// A %type can also define an undetermined nonterminal: eventually
// it must be defined as a nonterminal by a rule.
//
// If a %type is followed by a %token etc. then those latter directives may
// change the kind to symbol into terminal, but not their type.
//
// This function is called by the `symbol' rule
// Unknown symbol:
//
// Define the terminal as UNDETERMINED with %type, otherwise as `type'
//
// known symbol:
// ---------------------------------------------------------------------
// Second:
// ---------------------------------------------------------
// %token %type (-> d_typeDirective)
// ---------------------------------------------------------------------
// First:
// (%type -> UNDETERMINED)
// ---------------------------------------------------------------------
// %token mult.def'd OK, unless token's %type is specified
// and different from %type. If equal: warn
//
// %type OK, same as OK, same as upper right
// upper right
// ---------------------------------------------------------------------
void Parser::defineTerminal(string const &name, Symbol::Type type)
{
if (Symbol *sp = d_symtab.lookup(name)) // known symbol?
{
// known symbol: upper left alternative
if (not sp->isUndetermined() && not d_typeDirective)
{
multiplyDefined(sp);
return;
}
if (sp->sType().empty())
sp->setStype(d_field);
else if (sp->sType() == d_field)
wmsg <<
'`' << name << "' type repeatedly specified as <" <<
d_field << ">" << endl;
else // type clash
emsg <<
"can't redefine type <" << sp->sType() << "> of `" <<
name << "' to <" << d_field << ">" << endl;
}
else // new symbol: insert it as (provisional or definitive) terminal
d_symtab.insert
(
Symtab::value_type
(
name,
d_rules.insert
(
new Terminal(name,
d_typeDirective ?
Symbol::UNDETERMINED
:
type,
type == Symbol::CHAR_TERMINAL ?
d_scanner.number()
:
Terminal::DEFAULT,
d_association, d_field),
d_matched
)
)
);
}
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