private Parser <Value> GetAssignmentParser(Scope.Builder scopeBuilder, ErrorContext errorContext)
{
var assignmentParser =
from variableDefinition in GetVariableDefinitionParser(scopeBuilder, errorContext)
from assignmentOperator in Parse.Char('=').Token()
from value in _mainParser
select GetAssignmentExpression(scopeBuilder, variableDefinition.Name, value, variableDefinition.Mutable);
return(assignmentParser);
}
private Parser <Value> GetVariableParser(Scope.Builder scopeBuilder, ErrorContext errorContext)
{
var variableParser =
from variableDefinition in GetVariableDefinitionParser(scopeBuilder, errorContext)
select variableDefinition.Index.Type == Types.error ? default(Value) :
AllocateExpression(Types.Any, new[]
{
Instruction.ReadVariable(variableDefinition.Index)
});
return(variableParser);
}
private Value GetAssignmentExpression(Scope.Builder scopeBuilder, string variableName, Value valueExpression, bool mutable)
{
if (valueExpression.Type == Types.error)
{
return(valueExpression);
}
var instructions = new List <Instruction>();
var expression = Heap.GetExpression((int)valueExpression.Raw);
instructions.AddRange(expression.Instructions);
instructions.Add(Instruction.AssignVariable(scopeBuilder.GetOrCreateIndex(variableName), mutable));
valueExpression.RemoveRef();
return(AllocateExpression(expression.Type, instructions.ToArray()));
}
private Value GetVariableIndex(string variableName, Scope.Builder scopeBuilder, ErrorContext errorContext)
{
int index;
if (!scopeBuilder.TryGetIndex(variableName, out index))
{
var message = $"Unknown variable: '{variableName}'.";
if (errorContext.IsEmpty || errorContext.Peek().Message != message)
{
errorContext.AddError(new Error(message));
}
return(default(Value));
}
return(new Value(index));
}
private Parser <VariableDefinition> GetVariableDefinitionParser(Scope.Builder scopeBuilder, ErrorContext errorContext)
{
var variableDefinitionParser =
from mutableMarker in Parse.Char('$').Once().Optional()
from first in Parse.Letter.Once()
from rest in Parse.LetterOrDigit.Or(Parse.Chars('_', '-')).Many()
let name = new string(
mutableMarker.GetOrElse(Enumerable.Empty <char>())
.Concat(first)
.Concat(rest).ToArray())
select new VariableDefinition
{
Index = GetVariableIndex(name, scopeBuilder, errorContext),
Name = name,
Mutable = mutableMarker.IsDefined
};
return(variableDefinitionParser);
}
private Parser <Value> GetLiteralExpressionParser(Scope.Builder scopeBuilder, ErrorContext errorContext)
{
var booleanParser = GetBooleanLiteralParser();
var integerParser = GetIntegerLiteralParser();
var floatParser = GetFloatLiteralParser();
var typeParser = GetTypeLiteralParser();
var stringParser = GetStringLiteralParser();
var tupleParser = GetTupleLiteralParser();
var listParser = GetListLiteralParser();
var variableParser = GetVariableParser(scopeBuilder, errorContext);
var literalParser =
booleanParser
.Or(floatParser)
.Or(integerParser)
.Or(typeParser)
.Or(stringParser)
.Or(tupleParser)
.Or(listParser)
.Or(variableParser);
return(literalParser);
}
public GarplyParser(ErrorContext errorContext, Scope.Builder scopeBuilder)
{
Parser <Value> mainParser = null;
_mainParser = Parse.Ref(() => mainParser);
_errorContext = errorContext;
var expressionLiteralParser = GetExpressionLiteralParser();
var expressionParser = GetExprParser();
var evalParser = GetEvalParser();
var assignmentParser = GetAssignmentParser(scopeBuilder, errorContext);
var literalParser = GetLiteralExpressionParser(scopeBuilder, errorContext);
mainParser =
expressionLiteralParser.Or(
expressionParser).Or(
evalParser).Or(
assignmentParser).Or(
literalParser)
.Token();
_tryParse = mainParser.TryParse;
}
