/*
* => [captures...] expression
* or
* => [captures...] { code... }
* or
* (parameters...) => [captures...] expression
* or
* (parameters...) => [captures...] { code... }
*/
LambdaExpression ParseLambda(TupleExpression argumentList = null)
{
var lambda = LambdaExpression.Create(unit.Location);
// Parse parameter list
if (argumentList == null || argumentList.Count == 0)
{
if (unit.Match(LoreToken.OpenParen))
{
var parameters = ParseDeclarationArgumentList();
lambda.SetParameters(parameters);
}
}
else
{
var lst = new List <NamedParameter> ();
foreach (var argument in argumentList.Items)
{
var name = argument as NameExpression;
if (name == null)
{
throw LoreException.Create(unit.Location).Describe($"Invalid parameter list in lambda declaration.");
}
lst.Add(NamedParameter.Create(name));
}
lambda.SetParameters(lst);
}
// Expect arrow operator
unit.Expect(LoreToken.Operator, "=>");
// Create master code block
CodeBlock master = CodeBlock.Create(unit.Location);
// Parse captures
if (unit.Match(LoreToken.OpenBracket))
{
// Parse captures
unit.Expect(LoreToken.OpenBracket);
while (!unit.Match(LoreToken.CloseBracket))
{
var lex = unit.Read();
var capture = Capture.Create(unit, lex);
master.AddCapture(capture);
}
unit.Expect(LoreToken.CloseBracket);
}
// Parse block
if (unit.Match(LoreToken.OpenBrace))
{
var block = ParseBlockWithoutCaptures();
// Merge captures
master.Merge(block);
}
// Or parse expression
else
{
// Create return statement for the result of the expression
var retstmt = ReturnStatement.Create(unit.Location);
retstmt.SetExpression(ParseExpression());
// Create a new block with the return statement
var block = CodeBlock.Create(unit.Location);
block.AddChild(retstmt);
// Merge captures
master.Merge(block);
}
// Set the lambda body
lambda.SetBody(master);
Console.WriteLine(lambda);
return(lambda);
}
/*
* fn name (parameters...) -> type [captures...] {
* code...
* }
*/
FunctionDeclaration ParseFunction()
{
var function = FunctionDeclaration.Create(unit.Location);
unit.Expect(LoreToken.Keyword, "fn");
// Read the name of the function
var name = unit.Expect(LoreToken.Identifier);
function.SetName(name.Value);
// Read the parameter list
if (unit.Match(LoreToken.OpenParen))
{
function.SetParameters(ParseDeclarationArgumentList());
}
// Read the return type
if (unit.Accept(LoreToken.Operator, "->"))
{
var names = new List <NameExpression> ();
while (unit.Match(LoreToken.Identifier))
{
names.Add(ParseName());
if (!unit.Accept(LoreToken.Comma))
{
break;
}
}
if (names.Count == 1)
{
function.SetReturnType(names [0]);
}
else
{
function.SetReturnTuple(names);
}
}
// Create the function body
CodeBlock body = CodeBlock.Create(unit.Location);
// Parse captures
if (unit.Accept(LoreToken.OpenBracket))
{
while (!unit.Match(LoreToken.CloseBracket))
{
var lex = unit.Read();
var capture = Capture.Create(unit, lex);
body.AddCapture(capture);
}
unit.Expect(LoreToken.CloseBracket);
}
// Parse body
if (unit.Match(LoreToken.OpenBrace))
{
body = ParseBlock();
}
else if (unit.Accept(LoreToken.Operator, "=>"))
{
body.AddChild(ParseExpression());
}
// Return the function
function.SetBody(body);
return(function);
}
/// <summary>
/// Merge this code block with another one.
/// </summary>
/// <param name="other">The other code block.</param>
public void Merge(CodeBlock other)
{
Captures.AddRange(other.Captures.GroupBy(c => c.Identifier).Select(g => g.First()));
Children.AddRange(other.Children);
}
/// <summary>
/// Sets the body of the function.
/// </summary>
/// <returns>The body.</returns>
/// <param name="body">Body.</param>
public void SetBody(CodeBlock body)
{
this.body = body;
}
public virtual void Accept(CodeBlock block) => Update(block);