Initial commit of a lexer for the YANG data modeling language as defined in IETF RFC 7950 (https://tools.ietf.org/html/rfc7950).752/camoberg/yang

3 files changed, 152 insertions, 0 deletions

diff --git a/AUTHORS b/AUTHORS
index f7a7acad..dfe1fa9e 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -139,6 +139,7 @@ Other contributors, listed alphabetically, are:
 * Hong Minhee -- HTTP lexer
 * Michael Mior -- Awk lexer
 * Bruce Mitchener -- Dylan lexer rewrite
+* Carl Moberg -- YANG Lexer
 * Reuben Morais -- SourcePawn lexer
 * Jon Morton -- Rust lexer
 * Paulo Moura -- Logtalk lexer
diff --git a/pygments/lexers/_mapping.py b/pygments/lexers/_mapping.py
index acb71ad9..61103d37 100644
--- a/pygments/lexers/_mapping.py
+++ b/pygments/lexers/_mapping.py
@@ -476,6 +476,7 @@ LEXERS = {
     'XtlangLexer': ('pygments.lexers.lisp', 'xtlang', ('extempore',), ('*.xtm',), ()),
     'YamlJinjaLexer': ('pygments.lexers.templates', 'YAML+Jinja', ('yaml+jinja', 'salt', 'sls'), ('*.sls',), ('text/x-yaml+jinja', 'text/x-sls')),
     'YamlLexer': ('pygments.lexers.data', 'YAML', ('yaml',), ('*.yaml', '*.yml'), ('text/x-yaml',)),
+    'YangLexer': ('pygments.lexers.yang', 'YANG', ('yang', 'Yang'), ('*.yang',), ('application/yang',)),
     'ZeekLexer': ('pygments.lexers.dsls', 'Zeek', ('zeek', 'bro'), ('*.zeek', '*.bro'), ()),
     'ZephirLexer': ('pygments.lexers.php', 'Zephir', ('zephir',), ('*.zep',), ()),
     'ZigLexer': ('pygments.lexers.zig', 'Zig', ('zig',), ('*.zig',), ('text/zig',)),
diff --git a/pygments/lexers/yang.py b/pygments/lexers/yang.py
new file mode 100644
index 00000000..a4c25c51
--- /dev/null
+++ b/pygments/lexers/yang.py
@@ -0,0 +1,150 @@
+# -*- coding: utf-8 -*-
+"""
+    pygments.lexers.yang
+    ~~~~~~~~~~~~~~~~~~~~
+
+    Lexer for YANG (IETF RFC 6020) modules
+    https://tools.ietf.org/html/rfc6020
+"""
+
+from pygments.lexer import include, bygroups, RegexLexer
+from pygments.token import *
+import re
+
+__all__ = ['YangLexer']
+
+# TODO:
+#  - More testing:
+#   + for completeness, and
+#   + weird, but compliant line formatting
+#  - Support string concatenation with '+'
+#  - Look closer at ABNF in RFC6020 for more fine-grained types
+#    above and beyond the current (_str, _id, and _nodeid)
+#  - We don't support YANG extensions (i.e. <prefix>:<keyword> form)
+
+class YangLexer(RegexLexer):
+	name = 'YANG'
+	aliases = ['yang', 'Yang']
+	filenames = ['*.yang']
+	mimetypes = ['application/yang']
+
+	# Loose interpretations of ABNF in RFC 6020
+	# Single or double multi-line, or unquoted single-line string terminated
+	# by semicolon
+	_str = r'(\s+(?s)["\'].+?["\']|\s+[A-Za-z0-9\_\-\.\:\/\[\]]+)(;)'
+	_date = r'(["\']?[0-9]{4}\-[0-9]{2}\-[0-9]{2}["\']?)'
+	# Roughly equivalent to identifier-arg-str
+	_id = r'(["\']?[A-Za-z_][A-Za-z0-9\_\-\.\:]+["\']?)'
+	_nodeid = r'(["\']?[A-Za-z_][A-Za-z0-9\_\-\.\:\/]+["\']?)'
+	_instanceid = r'(["\']?\/[A-Za-z_][A-Za-z0-9\_\-\.\:\/]+["\']?)'
+
+	tokens = {
+		'whitespace_stmts': [
+			(r'\s+', Text)
+		],
+		'top_stmts': [
+			(r'(module\s+)' + _id, bygroups(Keyword.Namespace, String)),
+			(r'(submodule\s+)' + _id, bygroups(Keyword.Namespace, String)),
+		],
+		'module_header_stmts': [
+			(r'(yang-version\s+)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(namespace)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(prefix)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(belongs-to\s+)' + _id, bygroups(Token.Keyword, String)),
+		],
+		'linkage_stmts': [
+			(r'(import\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(include\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(revision-date\s+)' + _date, bygroups(Token.Keyword, String)),
+		],
+		'meta_stmts': [
+			(r'(organization)' + _str, bygroups(Token.Keyword, String.Doc, Token.Punctuation)),
+			(r'(contact)' + _str, bygroups(Token.Keyword, String.Doc, Token.Punctuation)),
+			(r'(description)' + _str, bygroups(Token.Keyword, String.Doc, Token.Punctuation)),
+			(r'(reference)' + _str, bygroups(Token.Keyword, String.Doc, Token.Punctuation)),
+			(r'(revision\s+)' + _date, bygroups(Token.Keyword, String)),
+		],
+		'data_def_stmts': [
+			(r'(container\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(leaf\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(leaf-list\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(list\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(choice\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(case\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(uses\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(refine\s+)' + _nodeid, bygroups(Token.Keyword, String)),
+			(r'(anyxml\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(config)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(presence)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(when)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(must)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(error-message)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(error-app-tag)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+		],
+		'body_stmts': [
+			(r'(extension\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(argument\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(if-feature\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(feature\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(identity\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(typedef\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(grouping\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(rpc\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(input)', Token.Keyword),
+			(r'(output)', Token.Keyword),
+			(r'(notification\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(deviation\s+)' + _instanceid, bygroups(Token.Keyword, String)),
+			(r'(deviate\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(augment\s+)' + _instanceid, bygroups(Token.Keyword, String)),
+			(r'(uses\s+)' + _id, bygroups(Token.Keyword, String)),
+
+		],
+		'type_stmts': [
+			(r'(type\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(units)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(default)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(status\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(reference\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(fraction-digits)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(range)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(length)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(pattern)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(enum\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(value)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(bit\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(path)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(require-instance)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(base\s+)' + _id, bygroups(Token.Keyword, String)),
+			(r'(min-elements)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(max-elements)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(ordered-by)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+		],
+		'list_stmts': [
+			(r'(key)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(unique)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+			(r'(mandatory)' + _str, bygroups(Token.Keyword, String, Token.Punctuation)),
+		],
+		'comment_stmts': [
+			(r'[^*/]', Comment.Multiline),
+			(r'/\*', Comment.Multiline, '#push'),
+			(r'\*/', Comment.Multiline, '#pop'),
+			(r'[*/]', Comment.Multiline),
+		],
+
+		'root': [
+			(r'{', Token.Punctuation),
+			(r'}', Token.Punctuation),
+			(r';', Token.Punctuation),
+			include('top_stmts'),
+			include('module_header_stmts'),
+			include('linkage_stmts'),
+			include('meta_stmts'),
+			include('data_def_stmts'),
+			include('body_stmts'),
+			include('type_stmts'),
+			include('list_stmts'),
+			(r'/\*', Comment.Multiline, 'comment_stmts'),
+			(r'//.*?$', Comment.Singleline),
+			include('whitespace_stmts'),
+		]
+	}
\ No newline at end of file