public Expression ParseHashLiteral()
{
var hash = new HashLiteral()
{
Token = this.currentToken, Pairs = new Dictionary <Expression, Expression>()
};
while (!this.IsPeekTokenTypeEqualTo(TokenType.RBRACE))
{
this.NextToken();
var key = this.ParseExpression(Precedence.LOWEST);
if (!this.Expect(TokenType.COLON))
{
return(null);
}
this.NextToken();
var value = this.ParseExpression(Precedence.LOWEST);
hash.Pairs[key] = value;
if (!this.IsPeekTokenTypeEqualTo(TokenType.RBRACE) && !this.Expect(TokenType.COMMA))
{
return(null);
}
}
if (!this.Expect(TokenType.RBRACE))
{
return(null);
}
return(hash);
}
private Object EvalHashLiteral(HashLiteral hash, Environment env)
{
var pairs = new Dictionary <HashKey, HashPair>();
foreach (var kvp in hash.Pairs)
{
var key = this.Eval(kvp.Key, env);
if (this.IsError(key))
{
return(key);
}
var hashKey = key as Hashable;
if (hashKey == null)
{
return(new Error()
{
Message = $"Unusable as hash key: {key.Type}"
});
}
var value = this.Eval(kvp.Value, env);
if (this.IsError(value))
{
return(value);
}
var hashed = hashKey.HashKey();
pairs[hashed] = new HashPair()
{
Key = key, Value = value
};
}
return(new Hash()
{
Pairs = pairs
});
}
