private static List <Spanned <FunctionParameter> > ParseFunctionParameters(
Context context,
ParserState state)
{
var parameters = new List <Spanned <FunctionParameter> >();
state.ConsumeOrError(TokenKind.LeftParenthesis);
if (state.Consume(TokenKind.RightParenthesis))
{
return(parameters);
}
do
{
var identifier = state.ConsumeOrError(TokenKind.Identifier);
state.ConsumeOrError(TokenKind.Colon);
var typeSignature = TypeSignatureParser.ParseTypeSignature(state);
var span = SourceSpan.Merge(identifier.Span, typeSignature.Span);
parameters.Add(
new Spanned <FunctionParameter>(
new FunctionParameter(
state.NodeIdGenerator.GetNextId(),
identifier,
typeSignature),
span));
} while (!state.IsAtEnd() && state.Consume(TokenKind.Comma));
state.ConsumeOrError(TokenKind.RightParenthesis);
return(parameters);
}
private static IStatement ParseFunctionDefinition(Context context, ParserState state)
{
var startSpan = state.Previous().Span;
var identifier = state.ConsumeOrError(TokenKind.Identifier);
var parameters = ParseFunctionParameters(context, state);
var returnTypeSignature = state.Consume(TokenKind.Colon)
? TypeSignatureParser.ParseTypeSignature(state)
: null;
var body = ParseBlock(context, state);
var endSpan = state.Previous().Span;
var span = SourceSpan.Merge(startSpan, endSpan);
return(new FunctionDefinition(
state.NodeIdGenerator.GetNextId(),
span,
identifier,
parameters,
body,
returnTypeSignature));
}
private static IStatement ParseVariableDefinition(Context context, ParserState state)
{
var startSpan = state.Previous().Span;
var identifier = state.ConsumeOrError(TokenKind.Identifier);
var typeSignature = state.Consume(TokenKind.Colon)
? TypeSignatureParser.ParseTypeSignature(state)
: null;
SourceSpan endSpan;
SourceSpan span;
if (state.Consume(TokenKind.Equal))
{
var initializer = ExpressionParser.ParseExpression(state);
endSpan = state.Previous().Span;
span = SourceSpan.Merge(startSpan, endSpan);
return(new VariableDefinition(
state.NodeIdGenerator.GetNextId(),
span,
identifier,
typeSignature,
initializer));
}
if (typeSignature == null)
{
throw new ParseException(identifier.Span, "type signature needed");
}
endSpan = state.Previous().Span;
span = SourceSpan.Merge(startSpan, endSpan);
return(new VariableDefinition(
state.NodeIdGenerator.GetNextId(),
span,
identifier,
typeSignature,
null));
}
