Introduce pip requirements file highlighting

Author: brettcannon

languages/pip-requirements.json

@@ -0,0 +1,5 @@
+{
+    "comments": {
+        "lineComment": "#"
+    }
+}

package.json

@@ -1482,7 +1482,31 @@
           "description": "Code executed when the kernel starts. Such as the default of '%matplotlib inline'. Individual lines can be placed in separate items of the array."
         }
       }
-    }
+    },
+    "languages": [
+      {
+        "id": "pip-requirements",
+        "aliases": [
+          "pip requirements",
+          "requirements.txt"
+        ],
+        "filenames": [
+          "requirements.txt"
+        ],
+        "filenamePatterns": [
+          "*-requirements.txt",
+          "requirements-*.txt"
+        ],
+        "configuration": "./languages/pip-requirements.json"
+      }
+    ],
+    "grammars": [
+      {
+        "language": "pip-requirements",
+        "scopeName": "source.pip-requirements",
+        "path": "./syntaxes/pip-requirements.tmLanguage.json"
+      }
+    ]
   },
   "scripts": {
     "vscode:prepublish": "tsc -p ./ && webpack",

src/test/pipRequirements/example-requirements.txt

@@ -0,0 +1,37 @@
+# https://www.python.org/dev/peps/pep-0508/#names
+This-name_has.everything42 # End-of-line comment.
+
+# https://www.python.org/dev/peps/pep-0508/#extras
+project[extras]
+
+# https://www.python.org/dev/peps/pep-0508/#versions
+# https://www.python.org/dev/peps/pep-0440/
+project > 2.0.0
+project~=1.0.0
+project>1.0.0,<2.0.0
+project==1.0.0.dev1
+
+# https://www.python.org/dev/peps/pep-0508/#environment-markers
+project;python_version>'3.0'
+project~=2.0.0;os_name=="linux"
+
+# https://pip.readthedocs.io/en/stable/reference/pip_install/#requirements-file-format
+# Continuation line.
+project \
+    >1.0.0
+
+# Options
+## Stand-alone w/o argument.
+--no-links
+## Stand-alone w/ argument.
+-c constraints.txt
+-e git://git.myproject.org/MyProject#egg=MyProject
+## Part of requirement.
+FooProject >= 1.2 --global-option="--no-user-cfg"
+
+# File path.
+./some/file
+some/file
+
+# URL.
+https://some-site.ca/project.whl

syntaxes/pip-requirements.tmLanguage.json

@@ -0,0 +1,77 @@
+{
+    "$schema": "https://raw.githubusercontent.com/martinring/tmlanguage/master/tmlanguage.json",
+    "name": "pip requirements",
+    "scopeName": "source.pip-requirements",
+    "patterns": [
+        {
+            "explanation": "Line continuation",
+            "match": "\\s*\\\\s*$",
+            "name": "constant.character.escape"
+        },
+        {
+            "match": "#.*",
+            "name": "comment.line.number-sign"
+        },
+        {
+            "begin": "'",
+            "end": "'",
+            "name": "string.quoted.single"
+        },
+        {
+            "begin": "\"",
+            "end": "\"",
+            "name": "string.quoted.double"
+        },
+        {
+            "match": "/?(\\S+/)+\\S*",
+            "name": "string.path"
+        },
+        {
+            "explanation": "project name",
+            "match": "^\\s*([A-Za-z0-9][A-Za-z0-9._-]*[A-Za-z0-9]|[A-Za-z0-9])",
+            "captures": {
+                "1": {
+                    "name": "entity.name.class"
+                }
+            }
+        },
+        {
+            "explanation": "extras",
+            "match": "\\[([^\\]]+)\\]",
+            "captures": {
+                "1": {
+                    "name": "entity.name.tag"
+                }
+            }
+        },
+        {
+            "explanation": "version specification",
+            "match": "(<|<=|!=|==|>=|>|~=|===)\\s*([\\w.*+!-]+)",
+            "captures": {
+                "1": {
+                    "name": "keyword.operator.comparison"
+                },
+                "2": {
+                    "name": "constant.numeric"
+                }
+            }
+        },
+        {
+            "explanation": "environment markers",
+            "match": ";\\s*(python_version|python_full_version|os_name|sys_platform|platform_release|platform_system|platform_version|platform_machine|platform_python_implementation|implementation_name|implementation_version|extra)\\s*(<|<=|!=|==|>=|>|~=|===)",
+            "captures":{
+                "1": {
+                    "name": "entity.name.selector"
+                },
+                "2": {
+                    "name": "keyword.operator.comparison"
+                }
+            }
+        },
+        {
+            "explanation": "command-line options (e.g. `--no-links` or `-c`)",
+            "match": "-[^\\s=]+",
+            "name": "entity.other.attribute-name"
+        }
+    ]
+}