Improve Plain Style support

close #557
nodeca · Dec 15, 2020 · 91f9662 · 91f9662
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commit 91f9662
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -19,7 +19,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Reduced nesting of `/lib` folder.
 - Parse numbers according to YAML 1.2 instead of YAML 1.1 (`01234` is now decimal,
   `0o1234` is octal, `1:23` is parsed as string instead of base60).
-- `dump()` no longer quotes `:` except when necessary, #470.
+- `dump()` no longer quotes `:`, `[`, `]`, `(`, `)` except when necessary, #470, #557.
 
 ### Added
 - Added `.mjs` (es modules) support.

diff --git a/lib/dumper.js b/lib/dumper.js
@@ -9,6 +9,7 @@ var DEFAULT_SCHEMA      = require('./schema/default');
 var _toString       = Object.prototype.toString;
 var _hasOwnProperty = Object.prototype.hasOwnProperty;
 
+var CHAR_BOM                  = 0xFEFF;
 var CHAR_TAB                  = 0x09; /* Tab */
 var CHAR_LINE_FEED            = 0x0A; /* LF */
 var CHAR_CARRIAGE_RETURN      = 0x0D; /* CR */
@@ -193,50 +194,60 @@ function isWhitespace(c) {
 function isPrintable(c) {
   return  (0x00020 <= c && c <= 0x00007E)
       || ((0x000A1 <= c && c <= 0x00D7FF) && c !== 0x2028 && c !== 0x2029)
-      || ((0x0E000 <= c && c <= 0x00FFFD) && c !== 0xFEFF /* BOM */)
+      || ((0x0E000 <= c && c <= 0x00FFFD) && c !== CHAR_BOM)
       ||  (0x10000 <= c && c <= 0x10FFFF);
 }
 
 // [34] ns-char ::= nb-char - s-white
 // [27] nb-char ::= c-printable - b-char - c-byte-order-mark
 // [26] b-char  ::= b-line-feed | b-carriage-return
-// [24] b-line-feed       ::=     #xA    /* LF */
-// [25] b-carriage-return ::=     #xD    /* CR */
-// [3]  c-byte-order-mark ::=     #xFEFF
-function isNsChar(c) {
-  return isPrintable(c) && !isWhitespace(c)
-    // byte-order-mark
-    && c !== 0xFEFF
-    // b-char
+// Including s-white (for some reason, examples doesn't match specs in this aspect)
+// ns-char ::= c-printable - b-line-feed - b-carriage-return - c-byte-order-mark
+function isNsCharOrWhitespace(c) {
+  return isPrintable(c)
+    && c !== CHAR_BOM
+    // - b-char
     && c !== CHAR_CARRIAGE_RETURN
     && c !== CHAR_LINE_FEED;
 }
 
-// Simplified test for values allowed after the first character in plain style.
-function isPlainSafe(c, prev) {
-  // Uses a subset of nb-char - c-flow-indicator - ":" - "#"
-  // where nb-char ::= c-printable - b-char - c-byte-order-mark.
-  return isPrintable(c) && c !== 0xFEFF
-    // - c-flow-indicator
-    && c !== CHAR_COMMA
-    && c !== CHAR_LEFT_SQUARE_BRACKET
-    && c !== CHAR_RIGHT_SQUARE_BRACKET
-    && c !== CHAR_LEFT_CURLY_BRACKET
-    && c !== CHAR_RIGHT_CURLY_BRACKET
-    // - "#"
-    // /* An ns-char preceding */ "#"
-    && ((c !== CHAR_SHARP) || (prev && isNsChar(prev)))
-    // - ":"
-    && ((c !== CHAR_COLON) || (prev && isNsChar(prev)))
-    // - but ": " isn't plain-safe
-    && !(prev && prev === CHAR_COLON && !isNsChar(c));
+// [127]  ns-plain-safe(c) ::= c = flow-out  ⇒ ns-plain-safe-out
+//                             c = flow-in   ⇒ ns-plain-safe-in
+//                             c = block-key ⇒ ns-plain-safe-out
+//                             c = flow-key  ⇒ ns-plain-safe-in
+// [128] ns-plain-safe-out ::= ns-char
+// [129]  ns-plain-safe-in ::= ns-char - c-flow-indicator
+// [130]  ns-plain-char(c) ::=  ( ns-plain-safe(c) - “:” - “#” )
+//                            | ( /* An ns-char preceding */ “#” )
+//                            | ( “:” /* Followed by an ns-plain-safe(c) */ )
+function isPlainSafe(c, prev, flowLevel) {
+  var cIsNsCharOrWhitespace = isNsCharOrWhitespace(c);
+  var cIsNsChar = cIsNsCharOrWhitespace && !isWhitespace(c);
+  return (
+    // ns-plain-safe
+    flowLevel < 0 ? // c = flow-in
+      cIsNsCharOrWhitespace
+      : cIsNsCharOrWhitespace
+        // - c-flow-indicator
+        && c !== CHAR_COMMA
+        && c !== CHAR_LEFT_SQUARE_BRACKET
+        && c !== CHAR_RIGHT_SQUARE_BRACKET
+        && c !== CHAR_LEFT_CURLY_BRACKET
+        && c !== CHAR_RIGHT_CURLY_BRACKET
+  )
+    // ns-plain-char
+    && c !== CHAR_SHARP // false on '#'
+    && !(prev === CHAR_COLON && !cIsNsChar) // false on ': '
+    || (isNsCharOrWhitespace(prev) && !isWhitespace(prev) && c === CHAR_SHARP) // change to true on '[^ ]#'
+    || (prev === CHAR_COLON && cIsNsChar); // change to true on ':[^ ]'
 }
 
 // Simplified test for values allowed as the first character in plain style.
 function isPlainSafeFirst(c) {
   // Uses a subset of ns-char - c-indicator
   // where ns-char = nb-char - s-white.
-  return isPrintable(c) && c !== 0xFEFF
+  // No support of ( ( “?” | “:” | “-” ) /* Followed by an ns-plain-safe(c)) */ ) part
+  return isPrintable(c) && c !== CHAR_BOM
     && !isWhitespace(c) // - s-white
     // - (c-indicator ::=
     // “-” | “?” | “:” | “,” | “[” | “]” | “{” | “}”
@@ -303,7 +314,7 @@ var STYLE_PLAIN   = 1,
 //    STYLE_LITERAL => no lines are suitable for folding (or lineWidth is -1).
 //    STYLE_FOLDED => a line > lineWidth and can be folded (and lineWidth != -1).
 function chooseScalarStyle(string, singleLineOnly, indentPerLevel, lineWidth,
-  testAmbiguousType, quotingType, forceQuotes) {
+  testAmbiguousType, quotingType, forceQuotes, flowLevel) {
 
   var i;
   var char = 0;
@@ -323,7 +334,7 @@ function chooseScalarStyle(string, singleLineOnly, indentPerLevel, lineWidth,
       if (!isPrintable(char)) {
         return STYLE_DOUBLE;
       }
-      plain = plain && isPlainSafe(char, prevChar);
+      plain = plain && isPlainSafe(char, prevChar, flowLevel);
       prevChar = char;
     }
   } else {
@@ -343,7 +354,7 @@ function chooseScalarStyle(string, singleLineOnly, indentPerLevel, lineWidth,
       } else if (!isPrintable(char)) {
         return STYLE_DOUBLE;
       }
-      plain = plain && isPlainSafe(char, prevChar);
+      plain = plain && isPlainSafe(char, prevChar, flowLevel);
       prevChar = char;
     }
     // in case the end is missing a \n
@@ -411,7 +422,7 @@ function writeScalar(state, string, level, iskey) {
     }
 
     switch (chooseScalarStyle(string, singleLineOnly, state.indent, lineWidth,
-      testAmbiguity, state.quotingType, state.forceQuotes && !iskey)) {
+      testAmbiguity, state.quotingType, state.forceQuotes && !iskey, state.flowLevel)) {
 
       case STYLE_PLAIN:
         return string;

diff --git a/test/issues/0521.js b/test/issues/0521.js
@@ -6,21 +6,22 @@ var yaml = require('../../');
 
 
 it('Don\'t quote strings with # without need', function () {
-  var data = yaml.load(`
-http://example.com/page#anchor: no#quotes#required
+  var required = `
+http://example.com/page#anchor: no:quotes#required
 parameter#fallback: 'quotes #required'
+'quotes: required': Visit [link](http://example.com/foo#bar)
 'foo #bar': key is quoted
-`);
+`.replace(/^\n/, '');
 
   var sample = {
-    'http://example.com/page#anchor': 'no#quotes#required',
+    'http://example.com/page#anchor': 'no:quotes#required',
     'parameter#fallback': 'quotes #required',
+    'quotes: required': 'Visit [link](http://example.com/foo#bar)',
     'foo #bar': 'key is quoted'
   };
 
-  assert.deepStrictEqual(
+  assert.strictEqual(
     yaml.dump(sample),
-    yaml.dump(data)
+    required
   );
-
 });