#include "builtins/builtins.h"
#include "precedence.h"
using namespace goose;
using namespace goose::eir;
using namespace goose::parse;
using namespace goose::builtins;
// Dollar is a low level operator: it doesn't expect a value rhs operand,
// but just an identifier eir instruction.
// So we can't use the convenient operator wrapper rule.
//
// Also, it works both as a prefix operator to construct a TVar,
// and as an infix operator (with a decl or TEXpr as the left value) to
// construct a Decl of the form "<type> $FOO" or a TDecl of the form
// "<TExpr> $FOO" (for instance $T $FOO)
namespace
{
Value BuildOrRetrieveTVar(
const Context& c, LocationId locationId, StringId name, bool forwarding )
{
if( name == "_"_sid )
return forwarding ? ToValue( TTVar( "_"_sid ) ) : ToValue( TVar( "_"_sid ) );
// Template name bindings are stored with a "$$" prefix so they don't
// collide with regular names.
auto captureIdentity = AppendToVectorTerm( c.identity(),
TERM( forwarding ? DecorateTTVarName( name ) : DecorateTVarName( name ) ) );
// Look up the TVar name. If it exists, then we're inside of a template function
// body, refering to a bound TVar, so we just return the stored value.
// Otherwise, we're in a template declaration and have to construct a new TVar.
Term result;
switch( c.env()->retrieveValue( captureIdentity, c.identity(), result ) )
{
case sema::Env::Status::Success:
return *EIRToValue( result );
case sema::Env::Status::AmbiguousMatch:
DiagnosticsManager::GetInstance().emitErrorMessage( locationId,
format( "unexpected ambiguous match when resolving '${}'.", name.str() ) );
return PoisonValue();
default:
break;
}
// No bound value was found: construct a TVar or a TTVar.
return forwarding ? ToValue( TTVar( name ) ) : ToValue( TVar( name ) );
}
bool ParsePrefixDollarOperator( Parser& p, LocationId locationId, uint32_t prec )
{
auto nameTerm = p.resolver()->consumeUnresolved();
if( !nameTerm )
{
DiagnosticsManager::GetInstance().emitSyntaxErrorMessage(
locationId, "expected an identifier after '$'.", 0 );
return false;
}
const auto* name = get_if< StringId >( &nameTerm->first );
if( !name )
{
DiagnosticsManager::GetInstance().emitSyntaxErrorMessage(
locationId, "expected an identifier after '$'.", 0 );
return false;
}
const auto& c = p.context();
auto val = BuildOrRetrieveTVar( c, nameTerm->second, *name, false );
auto loc = Location::CreateSpanningLocation( locationId, nameTerm->second );
val.setLocationId( loc );
p.pushValue( move( val ) );
return true;
}
bool ParsePrefixDollarDollarOperator( Parser& p, LocationId locationId, uint32_t prec )
{
auto nameTerm = p.resolver()->consumeUnresolved();
if( !nameTerm )
{
DiagnosticsManager::GetInstance().emitSyntaxErrorMessage(
locationId, "expected an identifier after '$$'.", 0 );
return false;
}
const auto* name = get_if< StringId >( &nameTerm->first );
if( !name )
{
DiagnosticsManager::GetInstance().emitSyntaxErrorMessage(
locationId, "expected an identifier after '$$'.", 0 );
return false;
}
const auto& c = p.context();
auto val = BuildOrRetrieveTVar( c, nameTerm->second, *name, true );
p.pushValue( move( val ) );
return true;
}
optional< uint32_t > InfixDollarPrecedence( const Parser& p )
{
const auto& leftVal = p.peekLastValue();
if( !leftVal )
return nullopt;
auto nameTerm = p.resolver()->lookAheadUnresolved();
if( !nameTerm )
return nullopt;
if( !holds_alternative< StringId >( nameTerm->first ) )
return nullopt;
if( !builtins::IsType( p.context(), *leftVal ) && !builtins::IsTExpr( *leftVal ) )
return nullopt;
return precedence::Decl;
}
bool ParseInfixDollarOperator( Parser& p, LocationId locationId, uint32_t prec )
{
const auto& leftVal = p.peekLastValue();
if( !leftVal )
return false;
if( !builtins::IsType( p.context(), *leftVal ) && !IsTExpr( *leftVal ) )
return false;
auto nameTerm = p.resolver()->consumeUnresolved();
const auto* name = get_if< StringId >( &nameTerm->first );
const auto& c = p.context();
auto val = BuildOrRetrieveTVar( c, nameTerm->second, *name, false );
// If the TVar was already bound, we may end up with something in val
// that isn't a TVar, which is an error.
if( !IsTVar( val ) )
{
DiagnosticsManager::GetInstance().emitSyntaxErrorMessage(
nameTerm->second, "expected an unbound identifier after '$'." );
return false;
}
auto loc = Location::CreateSpanningLocation( leftVal->locationId(), nameTerm->second );
auto typeOrTExpr = ValueToEIR( *p.popValue() );
auto tdecl = TDecl( move( typeOrTExpr ), *name );
p.pushValue( ToValue( move( tdecl ) ).setLocationId( loc ) );
return true;
}
} // namespace
namespace goose::builtins
{
void SetupDollarOp( Env& e )
{
Rule r( ParsePrefixDollarOperator, InfixDollarPrecedence, ParseInfixDollarOperator );
RegisterRule( e, "$"_sid, move( r ) );
Rule r2( ParsePrefixDollarDollarOperator );
RegisterRule( e, "$$"_sid, move( r2 ) );
}
} // namespace goose::builtins