public override AST.Node ToAST(Env env)
{
/// A return statement with an expression shall not appear in a function whose return type is void.
/// A return statement without an expression shall only appear in a function whose return type is void.
TFunc f = env.GetFuncType();
string returnLabel = env.GetReturnLabel();
if (expr != null)
{
if (f.ret.IsVoid)
{
throw new Error(Pos, "a return statement with an expression shall not appear a function whose return type is void");
}
AST.Expr e = expr.ToASTExpr(env).ValueTransform();
if (!Assign.SimpleAssignable(f.ret, e))
{
throw new ETypeError(Pos, string.Format("cannot assign {0} to {1}", e.Type, f.ret));
}
return(new AST.Return(returnLabel, e.ImplicitConvert(f.ret)));
}
else
{
if (!f.ret.IsVoid)
{
throw new Error(Pos, "a return statement without an expression shall only appear in a function whose return type is void");
}
return(new AST.Return(returnLabel, null));
}
}
public override AST.Node ToAST(Env env)
{
/// An iteration statement is a block.
env.PushBlockScope();
/// The controlling expression should have scalar type.
AST.Expr e = expr.ToASTExpr(env);
if (!e.Type.IsScalar)
{
throw new ETypeError(Pos, "the controlling expression of iteration statement should have scalar type");
}
/// The loop body is also a block.
env.PushBlockScope();
/// Add this loop to the environemnt.
env.PushLoop(this);
var b = body.ToASTCompoundStmt(env);
env.PopBreakable();
env.PopScope();
env.PopScope();
return(new AST.While(breakLabel, continueLabel, secondPlusLabel, firstLabel, e, b));
}
/// <summary>
/// A selection statement is a block whose scope is a strict subset
/// of the scope of its enclosing block.
///
/// The controlling expression of an if statement shall have scalar type.
/// </summary>
/// <param name="env"></param>
/// <returns></returns>
public override AST.Node ToAST(Env env)
{
env.PushBlockScope();
AST.Expr e = expr.ToASTExpr(env);
if (!e.Type.IsScalar)
{
throw new ETypeError(Pos, string.Format("expecting scalar type, given {0}", e.Type));
}
AST.Node t = then.ToAST(env);
AST.Node o = other != null?other.ToAST(env) : null;
env.PopScope();
var labels = env.AllocIfLabel();
return(new AST.If(e, t, o, labels.Item1, labels.Item2));
}
public override AST.Node ToAST(Env env)
{
env.PushBlockScope();
env.PushBlockScope();
env.PushLoop(this);
var b = body.ToASTCompoundStmt(env);
env.PopBreakable();
env.PopScope();
AST.Expr e = expr.ToASTExpr(env);
if (!e.Type.IsScalar)
{
throw new ETypeError(Pos, "the controlling expression of iteration statement should be have scalar type");
}
env.PopScope();
return(new AST.Do(breakLabel, continueLabel, secondPlusLabel, firstLabel, e, b));
}
