private BlockNode ParseBlock()
{
BlockNode retn = new BlockNode();
int expressionMatch = tokenStream.FindMatchingIndexNoAdvance(ExpressionTokenType.ExpressionOpen, ExpressionTokenType.ExpressionClose);
if (expressionMatch == -1)
{
retn.Release();
return(null);
}
tokenStream.Save();
tokenStream.Advance();
while (tokenStream.CurrentIndex != expressionMatch)
{
ASTNode statement = null;
int current = tokenStream.CurrentIndex;
if (!ParseStatement(ref statement))
{
retn.Release();
tokenStream.Restore();
return(null);
}
if (current == tokenStream.CurrentIndex)
{
throw new ParseException("fail recurse");
}
retn.statements.Add(statement);
}
tokenStream.Advance();
return(retn);
}
private bool ParseDeclaration(ref ASTNode node)
{
AttributeNode attrNode = null;
LightList <AttributeNode> attributes = LightList <AttributeNode> .Get();
while (ParseAttribute(ref attrNode))
{
attributes.Add(attrNode);
if (tokenStream.Current != ExpressionTokenType.ArrayAccessOpen)
{
break;
}
}
if (attributes.size == 0)
{
LightList <AttributeNode> .Release(ref attributes);
}
if (tokenStream.Current != ExpressionTokenType.Identifier)
{
return(false);
}
// modifiers? -> returnType -> name -> signature -> openBrace * closeBrace
tokenStream.Save();
bool isStatic = false;
if (tokenStream.Current == "static")
{
isStatic = true;
tokenStream.Advance();
}
ExpressionParser parser = new ExpressionParser(tokenStream);
StructList <LambdaArgument> signature = null;
TypeLookup typeLookup = default;
if (!parser.ParseTypePath(ref typeLookup))
{
goto fail;
}
tokenStream.Set(parser.GetTokenPosition());
parser.Release(false);
if (tokenStream.Current != ExpressionTokenType.Identifier)
{
goto fail;
}
string name = tokenStream.Current.value;
tokenStream.Advance();
// if semi colon then we have a field!
if (tokenStream.Current == ExpressionTokenType.SemiColon)
{
tokenStream.Advance();
node = new FieldNode()
{
name = name,
isStatic = isStatic,
attributes = attributes,
typeLookup = typeLookup
};
return(true);
}
if (tokenStream.Current != ExpressionTokenType.ParenOpen)
{
goto fail;
}
signature = StructList <LambdaArgument> .Get();
if (tokenStream.NextTokenIs(ExpressionTokenType.ParenClose))
{
tokenStream.Advance(2);
}
else
{
int matchingIndex = tokenStream.FindMatchingIndex(ExpressionTokenType.ParenOpen, ExpressionTokenType.ParenClose);
if (matchingIndex == -1)
{
goto fail;
}
TokenStream subStream = tokenStream.AdvanceAndReturnSubStream(matchingIndex);
subStream.Advance();
tokenStream.Advance();
if (!ExpressionParser.ParseSignature(subStream, signature))
{
goto fail;
}
for (int i = 0; i < signature.size; i++)
{
if (signature.array[i].type == null)
{
throw new ParseException($"When defining a method you must specify a type for all arguments. Found identifier {signature.array[i].identifier} but no type was given.");
}
}
}
if (tokenStream.Current != ExpressionTokenType.ExpressionOpen)
{
goto fail;
}
BlockNode block = ParseBlock();
node = new MethodNode()
{
body = block,
returnTypeLookup = typeLookup,
attributes = attributes,
name = name,
isStatic = isStatic,
signatureList = signature != null?signature.ToArray() : s_EmptySignature
};
StructList <LambdaArgument> .Release(ref signature);
parser.Release(false);
return(true);
fail:
{
tokenStream.Restore();
parser.Release(false);
typeLookup.Release();
signature?.Release();
return(false);
}
}
private bool ParseIfStatement(ref ASTNode node)
{
if (tokenStream.Current != ExpressionTokenType.If)
{
return(false);
}
LightList <ElseIfNode> statements = LightList <ElseIfNode> .Get();
tokenStream.Advance();
ASTNode condition = null;
if (!ParseParenExpression(ref condition))
{
throw new ParseException("Expected a condition statement wrapped in parentheses but failed.");
}
BlockNode thenBlock = ParseBlock();
if (thenBlock == null)
{
throw new ParseException("Expected a block statement following an if statement but failed to parse the block");
}
if (tokenStream.Current != ExpressionTokenType.ElseIf && tokenStream.Current != ExpressionTokenType.Else)
{
node = new IfStatementNode()
{
// elseIfStatements = statements.ToArray(),
condition = condition,
thenBlock = thenBlock
};
return(true);
}
while (tokenStream.Current == ExpressionTokenType.ElseIf)
{
tokenStream.Advance();
ASTNode elseIfCondition = null;
if (!ParseParenExpression(ref elseIfCondition))
{
throw new ParseException("Expected a condition statement wrapped in parentheses but failed.");
}
BlockNode block = ParseBlock();
if (block == null)
{
throw new ParseException("Expected a block statement following an if statement but failed to parse the block");
}
statements.Add(new ElseIfNode()
{
condition = elseIfCondition,
thenBlock = block
});
}
BlockNode elseBlock = null;
if (tokenStream.Current == ExpressionTokenType.Else)
{
tokenStream.Advance();
elseBlock = ParseBlock();
if (elseBlock == null)
{
throw new ParseException("Expected a block statement following an else statement but failed to parse the block");
}
}
node = new IfStatementNode()
{
condition = condition,
thenBlock = thenBlock,
elseIfStatements = statements.size == 0 ? null : statements.ToArray(),
elseBlock = elseBlock
};
statements.Release();
return(true);
}