private AST_Helper.Expression parseHashLiteral()
{
HashLiteral hashLiteral = new HashLiteral {
Token = this.curToken
};
while (!this.peekTokenIs(TokenHelper.TokenType.RBRACE))
{
this.nextToken();
AST_Helper.Expression keyExpr = this.parseExpression(Parser_Helper.precedence.LOWEST);
if (!this.expectPeek(TokenHelper.TokenType.COLON))
{
return(null);
}
this.nextToken();
AST_Helper.Expression valueExpr = this.parseExpression(Parser_Helper.precedence.LOWEST);
hashLiteral.Pairs.Add(keyExpr, valueExpr);
if (!this.peekTokenIs(TokenHelper.TokenType.RBRACE) && !this.expectPeek(TokenHelper.TokenType.COMMA))
{
return(null);
}
}
if (!this.expectPeek(TokenHelper.TokenType.RBRACE))
{
return(null);
}
return(hashLiteral);
}
private static Object_AST evalHashLiteral(HashLiteral hash, Environment_AST env)
{
Dictionary <HashKey, HashPair> pairs = new Dictionary <HashKey, HashPair>();
foreach (var item in hash.Pairs)
{
Object_AST key = Eval(item.Key, env);
if (key is Error_AST) //for recursive Eval calls, check the returned result of the recursive Eval. If an error, return rightaway. Otherwise we will get a
{
return(key); //higher level error obscuring the true source of error
}
IHashable hashKey = key as IHashable;
if (hashKey is null)
{
return(new Error_AST(string.Format("unusable as hash key: {0}", key.Type)));
}
Object_AST val = Eval(item.Value, env);
if (val is Error_AST) //for recursive Eval calls, check the returned result of the recursive Eval. If an error, return rightaway. Otherwise we will get a
{
return(val); //higher level error obscuring the true source of error
}
HashKey hashed = hashKey.HashKey();
pairs[hashed] = new HashPair {
Key = key, Value = val
};
}
return(new Hash_AST {
Pairs = pairs
});
}
