public bool ContainsAbove(string s) => parent == null?Contains(s) : (Contains(s) || parent.ContainsAbove(s));
MExp BuildExpression(MContent x, VirtualIdentifierTable t)
{
MExp BuildDis()
{
switch (x.type)
{
case "Identifier":
{
if (!t.ContainsAbove(x.value))
{
throw new LogicException("identifier [" + x.value + "] not found! ", x.line, x.column);
}
var cap = new CaptureTable();
if (!t.Contains(x.value))
{
cap.Add(x.value);
}
return(new MExpIdentifier()
{
identifier = x.value, captures = cap
});
}
case "FuncDef":
{
string[] fparams = x.subs.Slice(1, x.subs.Length - 1).Map((h) => h.value);
var g = new VirtualIdentifierTable()
{
parent = t
}.Fold(fparams, (h, v) => h.Insert(v));
var statements = BuildStatementGroup(x.subs[0], g);
return(new MExpFuncDef()
{
statements = statements,
formalParams = fparams,
captures = new CaptureTable().Fold(statements.statements, (a, p) => a.Merge(p.captures))
});
}
case "ExpFuncExec":
{
var func = BuildExpression(x.subs[0], t);
var aparams = x.subs.Slice(1, x.subs.Length - 1).Map((h) => BuildExpression(h, t));
var cap = func.captures.Fold(aparams, (h, v) => h.Merge(v.captures));
return(new MExpFuncExec()
{
func = func, actualParams = aparams, captures = cap
});
}
case "ExpArray":
{
var initValue = BuildExpression(x.subs[0], t);
var size = BuildExpression(x.subs[1], t);
var cap = initValue.captures.Merge(size.captures);
return(new MExpArray()
{
initValue = initValue, size = size, captures = cap
});
}
case "ExpIndex":
{
var arr = BuildExpression(x.subs[0], t);
var ind = BuildExpression(x.subs[1], t);
var cap = arr.captures.Merge(ind.captures);
return(new MExpIndex()
{
array = arr, index = ind, captures = cap
});
}
case "ExpAssign":
{
// Add the key first, if context does not contains.
if (x.subs[0].type == "Identifier" && !t.ContainsAbove(x.subs[0].value))
{
t.Add(x.subs[0].value);
}
var leftExp = BuildExpression(x.subs[0], t);
var rightExp = BuildExpression(x.subs[1], t);
var cap = leftExp.captures.Merge(rightExp.captures);
return(new MExpAssign()
{
op = x.value, leftExp = leftExp, rightExp = rightExp, captures = cap
});
}
case "ExpNegative":
{
var e = BuildExpression(x.subs[0], t);
return(new MExpNegative()
{
exp = e, captures = e.captures
});
}
case "ExpNot":
{
var e = BuildExpression(x.subs[0], t);
return(new MExpNot()
{
exp = e, captures = e.captures
});
}
/// These tags are distinct for priority purpose.
/// As grammer tree is here the priority can be ignored.
case "ExpLogic":
case "ExpMul":
case "ExpAdd":
case "ExpCmp":
{
var l = BuildExpression(x.subs[0], t);
var r = BuildExpression(x.subs[1], t);
return(new MExpCalc()
{
left = l, right = r, op = x.value, captures = l.captures.Merge(r.captures)
});
}
case "ExpIf":
{
var cond = BuildExpression(x.subs[0], t);
var fit = BuildExpression(x.subs[1], t);
var nfit = BuildExpression(x.subs[2], t);
var cap = cond.captures.Merge(fit.captures).Merge(nfit.captures);
return(new MExpIf()
{
cond = cond, fit = fit, nfit = nfit, captures = cap
});
}
case "Literal.Char":
return(new MExpLiteral()
{
value = new MChar(x.value[0])
});
case "Literal.Int":
return(new MExpLiteral()
{
value = new MInt(int.Parse(x.value)),
});
case "Literal.Float":
return(new MExpLiteral()
{
value = new MFloat(double.Parse(x.value))
});
}
throw new Exception("unknown expression type : " + x.type + " at line " + x.line);
}
var exp = BuildDis();
exp.line = x.line;
exp.col = x.column;
Debug.Assert(exp.captures != null);
return(exp);
}