enh(fortran) Add support for FORTRAN 77 style comments (#2416)

Closes #2310.
highlightjs · Feb 23, 2020 · d2e7493 · d2e7493
1 parent 83996aa
commit d2e7493
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Showing 4 changed files with 70 additions and 17 deletions.
diff --git a/CHANGES.md b/CHANGES.md
@@ -16,6 +16,7 @@ Core Changes:
 
 Language Improvements:
 
+- enh(fortran) Support Fortran 77 style comments (#2416) [Josh Goebel][]
 - (csharp) add support for `@identifier` style identifiers (#2414) [Josh Goebel][]
 - fix(elixir) Support function names with a slash (#2406) [Josh Goebel][]
 - fix(javascript) comma is allowed in a "value container" (#2403) [Josh Goebel][]

diff --git a/src/languages/fortran.js b/src/languages/fortran.js
@@ -6,12 +6,43 @@ Category: scientific
 */
 
 export default function(hljs) {
-  var PARAMS = {
+  const PARAMS = {
     className: 'params',
     begin: '\\(', end: '\\)'
   };
 
-  var F_KEYWORDS = {
+  const COMMENT = {
+    variants: [
+      hljs.COMMENT('!', '$', {relevance: 0}),
+      // allow Fortran 77 style comments
+      hljs.COMMENT('^C', '$', {relevance: 0})
+    ]
+  };
+
+  const NUMBER = {
+    className: 'number',
+    // regex in both fortran and irpf90 should match
+    begin: '(?=\\b|\\+|\\-|\\.)(?:\\.|\\d+\\.?)\\d*([de][+-]?\\d+)?(_[a-z_\\d]+)?',
+    relevance: 0
+  };
+
+  const FUNCTION_DEF = {
+    className: 'function',
+    beginKeywords: 'subroutine function program',
+    illegal: '[${=\\n]',
+    contains: [hljs.UNDERSCORE_TITLE_MODE, PARAMS]
+  };
+
+  const STRING = {
+    className: 'string',
+    relevance: 0,
+    variants: [
+      hljs.APOS_STRING_MODE,
+      hljs.QUOTE_STRING_MODE
+    ]
+  };
+
+  const KEYWORDS = {
     literal: '.False. .True.',
     keyword: 'kind do concurrent local shared while private call intrinsic where elsewhere ' +
       'type endtype endmodule endselect endinterface end enddo endif if forall endforall only contains default return stop then block endblock endassociate ' +
@@ -46,7 +77,7 @@ export default function(hljs) {
       'set_exponent shape size spacing spread sum system_clock tiny transpose trim ubound unpack verify achar iachar transfer ' +
       'dble entry dprod cpu_time command_argument_count get_command get_command_argument get_environment_variable is_iostat_end ' +
       'ieee_arithmetic ieee_support_underflow_control ieee_get_underflow_mode ieee_set_underflow_mode ' +
-      'is_iostat_eor move_alloc new_line selected_char_kind same_type_as extends_type_of'  +
+      'is_iostat_eor move_alloc new_line selected_char_kind same_type_as extends_type_of '  +
       'acosh asinh atanh bessel_j0 bessel_j1 bessel_jn bessel_y0 bessel_y1 bessel_yn erf erfc erfc_scaled gamma log_gamma hypot norm2 ' +
       'atomic_define atomic_ref execute_command_line leadz trailz storage_size merge_bits ' +
       'bge bgt ble blt dshiftl dshiftr findloc iall iany iparity image_index lcobound ucobound maskl maskr ' +
@@ -56,24 +87,19 @@ export default function(hljs) {
     name: 'Fortran',
     case_insensitive: true,
     aliases: ['f90', 'f95'],
-    keywords: F_KEYWORDS,
+    keywords: KEYWORDS,
     illegal: /\/\*/,
     contains: [
-      hljs.inherit(hljs.APOS_STRING_MODE, {className: 'string', relevance: 0}),
-      hljs.inherit(hljs.QUOTE_STRING_MODE, {className: 'string', relevance: 0}),
+      STRING,
+      FUNCTION_DEF,
+      // allow `C = value` for assignments so they aren't misdetected
+      // as Fortran 77 style comments
       {
-        className: 'function',
-        beginKeywords: 'subroutine function program',
-        illegal: '[${=\\n]',
-        contains: [hljs.UNDERSCORE_TITLE_MODE, PARAMS]
+        begin: /^C\s*=(?!=)/,
+        relevance: 0,
       },
-      hljs.COMMENT('!', '$', {relevance: 0}),
-      {
-        className: 'number',
-        // regex in both fortran and irpf90 should match
-        begin: '(?=\\b|\\+|\\-|\\.)(?:\\.|\\d+\\.?)\\d*([de][+-]?\\d+)?(_[a-z_\\d]+)?',
-        relevance: 0
-      }
+      COMMENT,
+      NUMBER
     ]
   };
 }
diff --git a/test/markup/fortran/comments.expect.txt b/test/markup/fortran/comments.expect.txt
@@ -0,0 +1,13 @@
+<span class="hljs-comment">C</span>
+<span class="hljs-comment">C  This program in FORTRAN 77 outputs "Hello, World!".</span>
+<span class="hljs-comment">C ====================================================</span>
+
+  <span class="hljs-comment">!===============================</span>
+  <span class="hljs-comment">!   This is a test subroutine</span>
+  <span class="hljs-comment">!===============================</span>
+
+<span class="hljs-comment">! another comment</span>
+
+C=<span class="hljs-number">2</span>
+C = <span class="hljs-number">2</span> <span class="hljs-comment">!correct</span>
+C =<span class="hljs-string">'boo'</span>
diff --git a/test/markup/fortran/comments.txt b/test/markup/fortran/comments.txt
@@ -0,0 +1,13 @@
+C
+C  This program in FORTRAN 77 outputs "Hello, World!".
+C ====================================================
+
+  !===============================
+  !   This is a test subroutine
+  !===============================
+
+! another comment
+
+C=2
+C = 2 !correct
+C ='boo'