Support various \def-like and \let-like commands (#167)

Signed-off-by: Jonas Dujava <jonas.dujava@gmail.com>

grammar.js

@@ -989,11 +989,14 @@ module.exports = grammar({
       ),
 
     old_command_definition: $ =>
-      seq(field('command', '\\def'), field('declaration', $.command_name)),
+      seq(
+        field('command', choice('\\def', '\\gdef', '\\edef', '\\xdef')),
+        field('declaration', $.command_name)
+      ),
 
     let_command_definition: $ =>
       seq(
-        field('command', '\\let'),
+        field('command', choice('\\let', '\\glet')),
         field('declaration', $.command_name),
         optional('='),
         field('implementation', $.command_name),

src/grammar.json

@@ -5593,8 +5593,25 @@
           "type": "FIELD",
           "name": "command",
           "content": {
-            "type": "STRING",
+            "type": "CHOICE",
-            "value": "\\def"
+            "members": [
+              {
+                "type": "STRING",
+                "value": "\\def"
+              },
+              {
+                "type": "STRING",
+                "value": "\\gdef"
+              },
+              {
+                "type": "STRING",
+                "value": "\\edef"
+              },
+              {
+                "type": "STRING",
+                "value": "\\xdef"
+              }
+            ]
           }
         },
         {
@@ -5614,8 +5631,17 @@
           "type": "FIELD",
           "name": "command",
           "content": {
-            "type": "STRING",
+            "type": "CHOICE",
-            "value": "\\let"
+            "members": [
+              {
+                "type": "STRING",
+                "value": "\\let"
+              },
+              {
+                "type": "STRING",
+                "value": "\\glet"
+              }
+            ]
           }
         },
         {

src/node-types.json

@@ -4572,6 +4572,10 @@
         "multiple": false,
         "required": true,
         "types": [
+          {
+            "type": "\\glet",
+            "named": false
+          },
           {
             "type": "\\let",
             "named": false
@@ -5501,6 +5505,18 @@
           {
             "type": "\\def",
             "named": false
+          },
+          {
+            "type": "\\edef",
+            "named": false
+          },
+          {
+            "type": "\\gdef",
+            "named": false
+          },
+          {
+            "type": "\\xdef",
+            "named": false
           }
         ]
       },
@@ -9167,6 +9183,10 @@
     "type": "\\documentclass",
     "named": false
   },
+  {
+    "type": "\\edef",
+    "named": false
+  },
   {
     "type": "\\end",
     "named": false
@@ -9207,6 +9227,14 @@
     "type": "\\fvolcite",
     "named": false
   },
+  {
+    "type": "\\gdef",
+    "named": false
+  },
+  {
+    "type": "\\glet",
+    "named": false
+  },
   {
     "type": "\\gls",
     "named": false
@@ -9631,6 +9659,10 @@
     "type": "\\vref",
     "named": false
   },
+  {
+    "type": "\\xdef",
+    "named": false
+  },
   {
     "type": "]",
     "named": false