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//===--- ParseTemplate.cpp - Template Parsing -----------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements parsing of C++ templates.
//
//===----------------------------------------------------------------------===//
#include "clang/Parse/Parser.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Parse/DeclSpec.h"
#include "clang/Parse/Scope.h"
using namespace clang;
/// ParseTemplateDeclaration - Parse a template declaration, which includes
/// the template parameter list and either a function of class declaration.
///
/// template-declaration: [C++ temp]
/// 'export'[opt] 'template' '<' template-parameter-list '>' declaration
Parser::DeclTy *Parser::ParseTemplateDeclaration(unsigned Context) {
assert((Tok.is(tok::kw_export) || Tok.is(tok::kw_template)) &&
"Token does not start a template declaration.");
// Consume the optional export token, if it exists, followed by the
// namespace token.
bool isExported = false;
if(Tok.is(tok::kw_export)) {
SourceLocation ExportLoc = ConsumeToken();
if(!Tok.is(tok::kw_template)) {
Diag(Tok.getLocation(), diag::err_expected_template);
return 0;
}
isExported = true;
}
SourceLocation TemplateLoc = ConsumeToken();
// Enter template-parameter scope.
ParseScope TemplateParmScope(this, Scope::TemplateParamScope);
// Try to parse the template parameters, and the declaration if
// successful.
DeclTy *TemplateDecl = 0;
if (Tok.is(tok::less) && NextToken().is(tok::greater)) {
// This is a template specialization. Just consume the angle
// brackets and parse the declaration or function definition that
// follows.
// FIXME: Record somehow that we're in an explicit specialization.
ConsumeToken();
ConsumeToken();
TemplateParmScope.Exit();
TemplateDecl = ParseDeclarationOrFunctionDefinition();
} else {
if(ParseTemplateParameters(0))
TemplateDecl = ParseDeclarationOrFunctionDefinition();
}
return TemplateDecl;
}
/// ParseTemplateParameters - Parses a template-parameter-list enclosed in
/// angle brackets.
bool Parser::ParseTemplateParameters(DeclTy* TmpDecl) {
// Get the template parameter list.
if(!Tok.is(tok::less)) {
Diag(Tok.getLocation(), diag::err_expected_less_after) << "template";
return false;
}
ConsumeToken();
// Try to parse the template parameter list.
if(ParseTemplateParameterList(0)) {
if(!Tok.is(tok::greater)) {
Diag(Tok.getLocation(), diag::err_expected_greater);
return false;
}
ConsumeToken();
}
return true;
}
/// ParseTemplateParameterList - Parse a template parameter list. If
/// the parsing fails badly (i.e., closing bracket was left out), this
/// will try to put the token stream in a reasonable position (closing
/// a statement, etc.) and return false.
///
/// template-parameter-list: [C++ temp]
/// template-parameter
/// template-parameter-list ',' template-parameter
bool Parser::ParseTemplateParameterList(DeclTy* TmpDecl) {
// FIXME: For now, this is just going to consume the template parameters.
// Eventually, we should pass the template decl AST node as a parameter and
// apply template parameters as we find them.
while(1) {
DeclTy* TmpParam = ParseTemplateParameter();
if(!TmpParam) {
// If we failed to parse a template parameter, skip until we find
// a comma or closing brace.
SkipUntil(tok::comma, tok::greater, true, true);
}
// Did we find a comma or the end of the template parmeter list?
if(Tok.is(tok::comma)) {
ConsumeToken();
} else if(Tok.is(tok::greater)) {
// Don't consume this... that's done by template parser.
break;
} else {
// Somebody probably forgot to close the template. Skip ahead and
// try to get out of the expression. This error is currently
// subsumed by whatever goes on in ParseTemplateParameter.
// TODO: This could match >>, and it would be nice to avoid those
// silly errors with template <vec<T>>.
// Diag(Tok.getLocation(), diag::err_expected_comma_greater);
SkipUntil(tok::greater, true, true);
return false;
}
}
return true;
}
/// ParseTemplateParameter - Parse a template-parameter (C++ [temp.param]).
///
/// template-parameter: [C++ temp.param]
/// type-parameter
/// parameter-declaration
///
/// type-parameter: (see below)
/// 'class' identifier[opt]
/// 'class' identifier[opt] '=' type-id
/// 'typename' identifier[opt]
/// 'typename' identifier[opt] '=' type-id
/// 'template' '<' template-parameter-list '>' 'class' identifier[opt]
/// 'template' '<' template-parameter-list '>' 'class' identifier[opt] = id-expression
Parser::DeclTy *Parser::ParseTemplateParameter() {
TryAnnotateCXXScopeToken();
if(Tok.is(tok::kw_class)
|| (Tok.is(tok::kw_typename) &&
NextToken().isNot(tok::annot_qualtypename))) {
return ParseTypeParameter();
} else if(Tok.is(tok::kw_template)) {
return ParseTemplateTemplateParameter();
} else {
// If it's none of the above, then it must be a parameter declaration.
// NOTE: This will pick up errors in the closure of the template parameter
// list (e.g., template < ; Check here to implement >> style closures.
return ParseNonTypeTemplateParameter();
}
return 0;
}
/// ParseTypeParameter - Parse a template type parameter (C++ [temp.param]).
/// Other kinds of template parameters are parsed in
/// ParseTemplateTemplateParameter and ParseNonTypeTemplateParameter.
///
/// type-parameter: [C++ temp.param]
/// 'class' identifier[opt]
/// 'class' identifier[opt] '=' type-id
/// 'typename' identifier[opt]
/// 'typename' identifier[opt] '=' type-id
Parser::DeclTy *Parser::ParseTypeParameter() {
assert((Tok.is(tok::kw_class) || Tok.is(tok::kw_typename)) &&
"A type-parameter starts with 'class' or 'typename'");
// Consume the 'class' or 'typename' keyword.
bool TypenameKeyword = Tok.is(tok::kw_typename);
SourceLocation KeyLoc = ConsumeToken();
// Grab the template parameter name (if given)
SourceLocation NameLoc;
IdentifierInfo* ParamName = 0;
if(Tok.is(tok::identifier)) {
ParamName = Tok.getIdentifierInfo();
NameLoc = ConsumeToken();
} else if(Tok.is(tok::equal) || Tok.is(tok::comma) ||
Tok.is(tok::greater)) {
// Unnamed template parameter. Don't have to do anything here, just
// don't consume this token.
} else {
Diag(Tok.getLocation(), diag::err_expected_ident);
return 0;
}
DeclTy *TypeParam = Actions.ActOnTypeParameter(CurScope, TypenameKeyword,
KeyLoc, ParamName, NameLoc);
// Grab a default type id (if given).
if(Tok.is(tok::equal)) {
SourceLocation EqualLoc = ConsumeToken();
TypeTy *DefaultType = ParseTypeName();
if(DefaultType)
Actions.ActOnTypeParameterDefault(TypeParam, DefaultType);
}
return TypeParam;
}
/// ParseTemplateTemplateParameter - Handle the parsing of template
/// template parameters.
///
/// type-parameter: [C++ temp.param]
/// 'template' '<' template-parameter-list '>' 'class' identifier[opt]
/// 'template' '<' template-parameter-list '>' 'class' identifier[opt] = id-expression
Parser::DeclTy* Parser::ParseTemplateTemplateParameter() {
assert(Tok.is(tok::kw_template) && "Expected 'template' keyword");
// Handle the template <...> part.
SourceLocation TemplateLoc = ConsumeToken();
if(!ParseTemplateParameters(0)) {
return 0;
}
// Generate a meaningful error if the user forgot to put class before the
// identifier, comma, or greater.
if(!Tok.is(tok::kw_class)) {
Diag(Tok.getLocation(), diag::err_expected_class_before)
<< PP.getSpelling(Tok);
return 0;
}
SourceLocation ClassLoc = ConsumeToken();
// Get the identifier, if given.
IdentifierInfo* ident = 0;
if(Tok.is(tok::identifier)) {
ident = Tok.getIdentifierInfo();
ConsumeToken();
} else if(Tok.is(tok::equal) || Tok.is(tok::comma) || Tok.is(tok::greater)) {
// Unnamed template parameter. Don't have to do anything here, just
// don't consume this token.
} else {
Diag(Tok.getLocation(), diag::err_expected_ident);
return 0;
}
// Get the a default value, if given.
OwningExprResult DefaultExpr(Actions);
if(Tok.is(tok::equal)) {
ConsumeToken();
DefaultExpr = ParseCXXIdExpression();
if(DefaultExpr.isInvalid()) {
return 0;
}
}
// FIXME: Add an action for template template parameters.
return 0;
}
/// ParseNonTypeTemplateParameter - Handle the parsing of non-type
/// template parameters (e.g., in "template<int Size> class array;").
///
/// template-parameter:
/// ...
/// parameter-declaration
///
/// NOTE: It would be ideal to simply call out to ParseParameterDeclaration(),
/// but that didn't work out to well. Instead, this tries to recrate the basic
/// parsing of parameter declarations, but tries to constrain it for template
/// parameters.
/// FIXME: We need to make a ParseParameterDeclaration that works for
/// non-type template parameters and normal function parameters.
Parser::DeclTy* Parser::ParseNonTypeTemplateParameter() {
SourceLocation StartLoc = Tok.getLocation();
// Parse the declaration-specifiers (i.e., the type).
// FIXME: The type should probably be restricted in some way... Not all
// declarators (parts of declarators?) are accepted for parameters.
DeclSpec DS;
ParseDeclarationSpecifiers(DS);
// Parse this as a typename.
Declarator ParamDecl(DS, Declarator::TemplateParamContext);
ParseDeclarator(ParamDecl);
if(DS.getTypeSpecType() == DeclSpec::TST_unspecified && !DS.getTypeRep()) {
// This probably shouldn't happen - and it's more of a Sema thing, but
// basically we didn't parse the type name because we couldn't associate
// it with an AST node. we should just skip to the comma or greater.
// TODO: This is currently a placeholder for some kind of Sema Error.
Diag(Tok.getLocation(), diag::err_parse_error);
SkipUntil(tok::comma, tok::greater, true, true);
return 0;
}
// Create the parameter.
DeclTy *Param = Actions.ActOnNonTypeTemplateParameter(CurScope, ParamDecl);
// Is there a default value? Parsing this can be fairly annoying because
// we have to stop on the first non-nested (paren'd) '>' as the closure
// for the template parameter list. Or a ','.
if(Tok.is(tok::equal)) {
// TODO: Implement default non-type values.
SkipUntil(tok::comma, tok::greater, true, true);
}
return Param;
}
/// AnnotateTemplateIdToken - The current token is an identifier that
/// refers to the template declaration Template, and is followed by a
/// '<'. Turn this template-id into a template-id annotation token.
void Parser::AnnotateTemplateIdToken(DeclTy *Template, const CXXScopeSpec *SS) {
assert(getLang().CPlusPlus && "Can only annotate template-ids in C++");
assert(Template && Tok.is(tok::identifier) && NextToken().is(tok::less) &&
"Parser isn't at the beginning of a template-id");
// Consume the template-name.
SourceLocation TemplateNameLoc = ConsumeToken();
// Consume the '<'.
SourceLocation LAngleLoc = ConsumeToken();
// Parse the optional template-argument-list.
TemplateArgList TemplateArgs;
if (Tok.isNot(tok::greater) && ParseTemplateArgumentList(TemplateArgs)) {
// Try to find the closing '>'.
SkipUntil(tok::greater, true, true);
// FIXME: What's our recovery strategy for failed template-argument-lists?
return;
}
if (Tok.isNot(tok::greater))
return;
// Determine the location of the '>'. We won't actually consume this
// token, because we'll be replacing it with the template-id.
SourceLocation RAngleLoc = Tok.getLocation();
Tok.setKind(tok::annot_template_id);
Tok.setAnnotationEndLoc(RAngleLoc);
Tok.setLocation(TemplateNameLoc);
if (SS && SS->isNotEmpty())
Tok.setLocation(SS->getBeginLoc());
TemplateIdAnnotation *TemplateId
= (TemplateIdAnnotation *)malloc(sizeof(TemplateIdAnnotation) +
sizeof(TemplateArgTy*) * TemplateArgs.size());
TemplateId->TemplateNameLoc = TemplateNameLoc;
TemplateId->Template = Template;
TemplateId->LAngleLoc = LAngleLoc;
TemplateId->NumArgs = TemplateArgs.size();
TemplateArgTy **Args = (TemplateArgTy**)(TemplateId + 1);
for (unsigned Arg = 0, ArgEnd = TemplateArgs.size(); Arg != ArgEnd; ++Arg)
Args[Arg] = TemplateArgs[Arg];
Tok.setAnnotationValue(TemplateId);
// In case the tokens were cached, have Preprocessor replace them with the
// annotation token.
PP.AnnotateCachedTokens(Tok);
}
/// ParseTemplateArgument - Parse a C++ template argument (C++ [temp.names]).
///
/// template-argument: [C++ 14.2]
/// assignment-expression
/// type-id
/// id-expression
Parser::OwningTemplateArgResult Parser::ParseTemplateArgument() {
// FIXME: Implement this!
return TemplateArgError();
}
/// ParseTemplateArgumentList - Parse a C++ template-argument-list
/// (C++ [temp.names]). Returns true if there was an error.
///
/// template-argument-list: [C++ 14.2]
/// template-argument
/// template-argument-list ',' template-argument
bool Parser::ParseTemplateArgumentList(TemplateArgList &TemplateArgs) {
while (true) {
OwningTemplateArgResult Arg = ParseTemplateArgument();
if (Arg.isInvalid()) {
SkipUntil(tok::comma, tok::greater, true, true);
return true;
}
else
TemplateArgs.push_back(Arg.release());
// If the next token is a comma, consume it and keep reading
// arguments.
if (Tok.isNot(tok::comma)) break;
// Consume the comma.
ConsumeToken();
}
return Tok.isNot(tok::greater);
}