Feature #4276: Allow use of quotes in symbol syntactic sugar for hashes

• Status: Closed
• Priority: Normal
• Assignee: matz (Yukihiro Matsumoto)
• Target version: 2.6

[tbenst (Tyler Benster)]

Current syntactic sugar allows this:

hash = {Alabama: "AL"}

This feature request is to also allow symbols delimited by quotes (and thus able to contain a whitespace) to use an equivalent syntactic sugar:

hash2 = {"Rhode Island": "RI"}

[nobu (Nobuyoshi Nakada)]

Hi,

At Thu, 13 Jan 2011 10:17:23 +0900,
Tyler Benster wrote in [ruby-core:34453]:

Current syntactic sugar allows this:

hash = {Alabama: "AL"}

This feature request is to also allow symbols delimited by quotes (and thus able to contain a whitespace) to use an equivalent syntactic sugar:

hash2 = {"Rhode Island": "RI"}

I've forgotten to post the patch.

diff --git i/parse.y w/parse.y
index 06f96ce..0cacdd5 100644
--- i/parse.y
+++ w/parse.y
@@ -380,6 +380,8 @@ static NODE *ret_args_gen(struct parser_params*,NODE*);
 static NODE *arg_blk_pass(NODE*,NODE*);
 static NODE *new_yield_gen(struct parser_params*,NODE*);
 #define new_yield(node) new_yield_gen(parser, (node))
+static NODE *dsym_node_gen(struct parser_params*,NODE*);
+#define dsym_node(node) dsym_node_gen(parser, (node))
 
 static NODE *gettable_gen(struct parser_params*,ID);
 #define gettable(id) gettable_gen(parser,(id))
@@ -678,12 +680,12 @@ static void token_info_pop(struct parser_params*, const char *token);
 	keyword__FILE__
 	keyword__ENCODING__
 
-%token <id>   tIDENTIFIER tFID tGVAR tIVAR tCONSTANT tCVAR tLABEL
+%token <id>   tIDENTIFIER tFID tGVAR tIVAR tCONSTANT tCVAR tLABEL tLABEL_END
 %token <node> tINTEGER tFLOAT tSTRING_CONTENT tCHAR
 %token <node> tNTH_REF tBACK_REF
 %token <num>  tREGEXP_END
 
-%type <node> singleton strings string string1 xstring regexp
+%type <node> singleton strings string string1 xstring regexp string_body
 %type <node> string_contents xstring_contents regexp_contents string_content
 %type <node> words qwords word_list qword_list word
 %type <node> literal numeric dsym cpath
@@ -3841,12 +3843,18 @@ string		: tCHAR
 		    }
 		;
 
-string1		: tSTRING_BEG string_contents tSTRING_END
+string_body	: tSTRING_BEG string_contents
 		    {
-		    /*%%%*/
 			$$ = $2;
+		    }
+		;
+
+string1		: string_body tSTRING_END
+		    {
+		    /*%%%*/
+			$$ = $1;
 		    /*%
-			$$ = dispatch1(string_literal, $2);
+			$$ = dispatch1(string_literal, $1);
 		    %*/
 		    }
 		;
@@ -4199,26 +4207,7 @@ dsym		: tSYMBEG xstring_contents tSTRING_END
 		    {
 			lex_state = EXPR_END;
 		    /*%%%*/
-			if (!($$ = $2)) {
-			    $$ = NEW_LIT(ID2SYM(rb_intern("")));
-			}
-			else {
-			    VALUE lit;
-
-			    switch (nd_type($$)) {
-			      case NODE_DSTR:
-				nd_set_type($$, NODE_DSYM);
-				break;
-			      case NODE_STR:
-				lit = $$->nd_lit;
-				$$->nd_lit = ID2SYM(rb_intern_str(lit));
-				nd_set_type($$, NODE_LIT);
-				break;
-			      default:
-				$$ = NEW_NODE(NODE_DSYM, Qnil, 1, NEW_LIST($$));
-				break;
-			    }
-			}
+			$$ = dsym_node($2);
 		    /*%
 			$$ = dispatch1(dyna_symbol, $2);
 		    %*/
@@ -4761,6 +4750,15 @@ assoc		: arg_value tASSOC arg_value
 			$$ = dispatch2(assoc_new, $1, $2);
 		    %*/
 		    }
+		| string_body tLABEL_END arg_value
+		    {
+		    /*%%%*/
+			$$ = list_append(NEW_LIST(dsym_node($1)), $3);
+		    /*%
+			$$ = dispatch1(dyna_symbol, $1);
+			$$ = dispatch2(assoc_new, $$, $3);
+		    %*/
+		    }
 		;
 
 operation	: tIDENTIFIER
@@ -5334,6 +5332,7 @@ rb_parser_compile_file(volatile VALUE vparser, const char *f, VALUE file, int st
 #define STR_FUNC_QWORDS 0x08
 #define STR_FUNC_SYMBOL 0x10
 #define STR_FUNC_INDENT 0x20
+#define STR_FUNC_LABEL  0x40
 
 enum string_type {
     str_squote = (0),
@@ -5925,6 +5924,8 @@ parser_tokadd_string(struct parser_params *parser,
 
 #define NEW_STRTERM(func, term, paren) \
 	rb_node_newnode(NODE_STRTERM, (func), (term) | ((paren) << (CHAR_BIT * 2)), 0)
+#define IS_LABEL_SUFFIX(n) (peek_n(':',(n)) && !peek_n(':', (n)+1))
+#define MAYBE_LABEL() (IS_LABEL_POSSIBLE() ? STR_FUNC_LABEL : 0)
 
 static int
 parser_parse_string(struct parser_params *parser, NODE *quote)
@@ -5946,6 +5947,10 @@ parser_parse_string(struct parser_params *parser, NODE *quote)
 	    quote->nd_func = -1;
 	    return ' ';
 	}
+	if ((func & STR_FUNC_LABEL) && IS_LABEL_SUFFIX(0)) {
+	    lex_state = EXPR_BEG;
+	    return tLABEL_END;
+	}
 	if (!(func & STR_FUNC_REGEXP)) return tSTRING_END;
         set_yylval_num(regx_options());
 	return tREGEXP_END;
@@ -6533,7 +6538,6 @@ parser_prepare(struct parser_params *parser)
 #define IS_BEG() (lex_state == EXPR_BEG || lex_state == EXPR_MID || lex_state == EXPR_VALUE || lex_state == EXPR_CLASS)
 #define IS_SPCARG(c) (IS_ARG() && space_seen && !ISSPACE(c))
 #define IS_LABEL_POSSIBLE() ((lex_state == EXPR_BEG && !cmd_state) || IS_ARG())
-#define IS_LABEL_SUFFIX(n) (peek_n(':',(n)) && !peek_n(':', (n)+1))
 
 #ifndef RIPPER
 #define ambiguous_operator(op, syn) ( \
@@ -6849,7 +6853,7 @@ parser_yylex(struct parser_params *parser)
 	return '>';
 
       case '"':
-	lex_strterm = NEW_STRTERM(str_dquote, '"', 0);
+	lex_strterm = NEW_STRTERM(str_dquote | MAYBE_LABEL(), '"', 0);
 	return tSTRING_BEG;
 
       case '`':
@@ -6868,7 +6872,7 @@ parser_yylex(struct parser_params *parser)
 	return tXSTRING_BEG;
 
       case '\'':
-	lex_strterm = NEW_STRTERM(str_squote, '\'', 0);
+	lex_strterm = NEW_STRTERM(str_squote | MAYBE_LABEL(), '\'', 0);
 	return tSTRING_BEG;
 
       case '?':
@@ -8987,6 +8991,32 @@ new_args_gen(struct parser_params *parser, NODE *m, NODE *o, ID r, NODE *p, ID b
     ruby_sourceline = saved_line;
     return node;
 }
+
+static NODE*
+dsym_node_gen(struct parser_params *parser, NODE *node)
+{
+    if (!node) {
+	node = NEW_LIT(ID2SYM(rb_intern("")));
+    }
+    else {
+	VALUE lit;
+
+	switch (nd_type(node)) {
+	  case NODE_DSTR:
+	    nd_set_type(node, NODE_DSYM);
+	    break;
+	  case NODE_STR:
+	    lit = node->nd_lit;
+	    node->nd_lit = ID2SYM(rb_intern_str(lit));
+	    nd_set_type(node, NODE_LIT);
+	    break;
+	  default:
+	    node = NEW_NODE(NODE_DSYM, Qnil, 1, NEW_LIST(node));
+	    break;
+	}
+    }
+    return node;
+}
 #endif /* !RIPPER */
 
 static void

---

Nobu Nakada

[nahi (Hiroshi Nakamura)]

• Description updated (diff)
• Category set to core
• Status changed from Open to Assigned
• Assignee set to matz (Yukihiro Matsumoto)

[mame (Yusuke Endoh)]

• Target version set to 2.6

[bitsweat (Jeremy Daer)]

This would improve a lot of my code that's punctuated with { foo: bar, :'hoge' => piyo }. Switching syntax is a mental and visual interruption.

I hope Ruby 2 supports this quoted-symbol syntax from the first day it's released, so everyone can rely on it. Please consider this patch for preview2!

[drbrain (Eric Hodel)]

Sorry, this feature is too late for 2.0.0

[nobu (Nobuyoshi Nakada)]

One of the reason I didn't introduce this was, a few bundled scripts had compatibility issue when once I tried.

[nobu (Nobuyoshi Nakada)]

• Has duplicate Feature #9047: Alternate hash key syntax for symbols added

[nobu (Nobuyoshi Nakada)]

• Description updated (diff)

[nobu (Nobuyoshi Nakada)]

Updated with the test in [Feature #4935]: https://github.com/ruby/ruby/pull/684

[rosenfeld (Rodrigo Rosenfeld Rosas)]

Great, from the test it seems to allow interpolation. Could you please confirm I understood it correctly?

[matz (Yukihiro Matsumoto)]

• Status changed from Assigned to Feedback

I am not against the idea, but I want to make sure that key will be symbol, since some may expect

{"foo bar": 12}

to be a hash with string key, especially who is familiar with JSON.

Matz.

[nobu (Nobuyoshi Nakada)]

Rodrigo Rosenfeld Rosas wrote:

Great, from the test it seems to allow interpolation. Could you please confirm I understood it correctly?

Yes, it is allowed inside double quotes, but not single quotes.
Other terminators (e.g., %(...)) cause syntax errors.

[Ajedi32 (Andrew M)]

Yukihiro Matsumoto wrote:

I am not against the idea, but I want to make sure that key will be symbol,

Yes, I believe that was the intention. E.g.

# Currently, Hashes have syntactic sugar which allows:
{:key => "Value"} == {key: "Value"} #=> true

# This feature request is to allow:
{:"some key" => "Value"} == {"some key": "Value"} #=> true

[nobu (Nobuyoshi Nakada)]

OK, I commit the previous patch.
Yell if you don't like it.

[nobu (Nobuyoshi Nakada)]

• Status changed from Feedback to Closed
• % Done changed from 0 to 100

Applied in changeset r47649.

---

parse.y: quoted ID key

• parse.y (assoc): allow quoted ID as a key of a hash literal.
  [ruby-core:34453] [Feature #4276]

[nobu (Nobuyoshi Nakada)]

Just a note: last evening at RubyKaigi 2014, talked to matz about this issue, and got his approval to introduce this to see if anyone rants.

[etienne (Étienne Barrié)]

Hi, any reason it doesn't work with inner hashes or arrays?

{ foo: {} } # => {:foo=>{}}
{ 'foo': {} }
# SyntaxError: (irb):2: syntax error, unexpected '{'
{ 'foo': [] }
SyntaxError: (irb):1: syntax error, unexpected '['

[nobu (Nobuyoshi Nakada)]

• Related to Bug #10653: do-end block in ternary operator is syntax error added