//var function functionCall ({function})() a=b
public static JsExpression ParseProgram(List <Token> list)
{
JsExpression program = new JsExpression("", null);
current = program;
index = 0;
for (; index < list.Count; index++)
{
var item = list[index];
switch (item.type)
{
case TokenType.VAR:
current = ParseVar(list);
program.child.Add(current);
break;
case TokenType.FUNCTION:
current = ParseFunction(list);
program.child.Add(current);
break;
case TokenType.OpenParenthese:
current = ParseLambdaCall(list);
program.child.Add(current);
break;
case TokenType.IDENTIFY:
switch (list[index + 1].type)
{
case TokenType.BIND: //=
current = ParseAssign(list);
break;
case TokenType.SemiColon: //identifier
current = ParseIdentify(list);
index++; //match ;
break;
case TokenType.POINT: //call method or get field or set field or add new field
{
bool needMatchSemiColon = false;
if (LookAhead(list, index, 3, TokenType.OpenParenthese) ||
LookAhead(list, index, 3, TokenType.SemiColon)) //if method call
{
needMatchSemiColon = true;
}
current = ParsePointExpression(list);
// method call and get field need match ;
// now only check method call
// field get should not appear
if (needMatchSemiColon)
{
index++; //match ;
}
}
break;
case TokenType.EQ:
case TokenType.UNEQ:
case TokenType.LT:
case TokenType.GE:
case TokenType.LE:
case TokenType.GT:
case TokenType.AND:
case TokenType.OR:
current = ParseBool(list);
index++; //match ;
break;
default:
//func call
current = ParseFunctionCall(list);
index++; //match ;
break;
}
program.child.Add(current);
break;
case TokenType.NUMBER: // num | Math Exp | Bool Exp
if (isMathOperation(list[index + 1]))
{
current = ParseRelation(list);
}
else if (isBoolOperation(list[index + 1]))
{
current = ParseBool(list);
}
else
{
current = new JsExpression(list[index].name, program);
}
index++; //match ;
program.child.Add(current);
break;
case TokenType.STRING:
current = new JsExpression(item.name, current);
index++; //match ;
program.child.Add(current);
break;
default:
exceptions.Add(new Exception(current.value + " is an unknow expression"));
break;
}
current = program;
}
return(program);
}
//expList 内所有表达式都需要；
//有的内部已经match了；
//funcCall，PointExp没有match
public static JsExpression ParseExpList(List <Token> list)
{
JsExpression expList = new JsExpression("{", current);
current = expList;
index++;
while (list[index].type != TokenType.CloseBrace)
{
var item = list[index];
switch (item.type)
{
case TokenType.VAR: // already matched ;
expList.child.Add(ParseVar(list));
break;
case TokenType.FUNCTION: // already matched ;
expList.child.Add(ParseFunction(list));
break;
case TokenType.OpenParenthese:
current = ParseLambdaCall(list);
expList.child.Add(current);
current = expList;
index++; // match ;
break;
case TokenType.IDENTIFY:
switch (list[index + 1].type)
{
case TokenType.BIND: //=
// already matched ;
expList.child.Add(ParseAssign(list));
break;
case TokenType.POINT: //a.b()| a.b=1 |a.b
{
bool isMethodCall = false;
if (LookAhead(list, index, 3, TokenType.OpenParenthese)) //if method call
{
isMethodCall = true;
}
expList.child.Add(ParsePointExpression(list));
// method call and get field need match ;
// now only check method call
// field get should not appear
if (isMethodCall)
{
index++; //match ;
}
}
break;
default:
//func call
expList.child.Add(ParseFunctionCall(list));
index++; //match ;
break;
}
break;
case TokenType.IF: // no need to macth ;
expList.child.Add(ParseIf(list));
break;
case TokenType.WHILE: // no need to macth ;
expList.child.Add(ParseWhile(list));
break;
case TokenType.RETURN: // already matched ;
expList.child.Add(ParseReturn(list));
break;
default:
exceptions.Add(new Exception("undefine indentifier"));
break;
}
index++;//match }
}
current = expList.parent;
return(expList);
}
//a=num|function|(|indentify|new identify
public static JsExpression ParseAssign(List <Token> list)
{
JsExpression assignExp = new JsExpression("=", current);
current = assignExp;
assignExp.child.Add(ParseIdentify(list));
index++;
(list[index].type == TokenType.BIND).OrThrows("expected '='");
index++;
switch (list[index].type)
{
case TokenType.NUMBER:
assignExp.child.Add(GetSingleOrMathExpressionItem(list));
break;
case TokenType.IDENTIFY: //var|function call|a.b|bool
switch (list[index + 1].type)
{
case TokenType.OpenParenthese: //function call
assignExp.child.Add(ParseFunctionCall(list));
break;
case TokenType.SemiColon: //num or var
assignExp.child.Add(new JsExpression(list[index].name, current));
break;
case TokenType.POINT: //PointExp
assignExp.child.Add(ParsePointExpression(list));
break;
case TokenType.ADD: // Math Exp
case TokenType.SUB:
case TokenType.MUL:
case TokenType.DIV:
assignExp.child.Add(ParseRelation(list));
break;
case TokenType.AND:
case TokenType.OR:
case TokenType.EQ:
case TokenType.UNEQ:
case TokenType.LT:
case TokenType.GE:
case TokenType.LE:
case TokenType.GT: //Bool Exp
assignExp.child.Add(ParseBool(list));
break;
}
break;
case TokenType.FUNCTION:
assignExp.child.Add(ParseFunction(list));
break;
case TokenType.OpenParenthese:
index++; //pass ( ;annoymous function
assignExp.child.Add(ParseFunction(list));
break;
case TokenType.NEW:
assignExp.child.Add(ParseNewExpression(list));
break;
default:
assignExp.child.Add(new JsExpression(list[index].name, assignExp));
break;
}
index++;//match ;
(list[index].type == TokenType.SemiColon).OrThrows("expected a semicolon");
current = assignExp.parent;
return(assignExp);
}
public JsFunction(string[] args, JsExpression body, Env env)
{
this.args = args;
this.body = body;
this.env = env;
}