examples/yaml: stub added

examples/yaml/README.md

+# yaml
+
+PLACE A SHORT DESCRIPTION HERE
+
+Author: AUTHOR'S NAME <EMAIL>, AFFILIATION
+
+
+## License
+
+yaml is open source software under the [Apache 2.0 License](https://www.apache.org/licenses/LICENSE-2.0)
+
+Copyright YEAR AUTHOR'S NAME <EMAIL>, AFFILIATION
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    https://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.

examples/yaml/example.dsl

+Life is but a walking shadow

examples/yaml/example.json

+// json-example
+
+{
+  "object": { "one": 1, "two": 2, "three": ["3"] },
+  "array": ["one", 2, 3],
+  "string": "string example",
+  "true": true,
+  "false": false,
+  "null": null
+}

examples/yaml/tst_yaml_grammar.py

+#!/usr/bin/python3
+
+"""tst_yaml_grammar.py - runs the unit tests for the yaml-grammar
+"""
+
+import os
+import sys
+
+LOGGING = False
+
+sys.path.append(r'/home/eckhart/Entwicklung/DHParser')
+
+scriptpath = os.path.dirname(__file__)
+
+
+try:
+    from DHParser import dsl
+    import DHParser.log
+    from DHParser import testing
+except ModuleNotFoundError:
+    print('Could not import DHParser. Please adjust sys.path in file '
+          '"%s" manually' % __file__)
+    sys.exit(1)
+
+
+def recompile_grammar(grammar_src, force):
+    grammar_tests_dir = os.path.join(scriptpath, 'grammar_tests')
+    testing.create_test_templates(grammar_src, grammar_tests_dir)
+    with DHParser.log.logging(False):
+        # recompiles Grammar only if it has changed
+        if not dsl.recompile_grammar(grammar_src, force=force,
+                notify=lambda: print('recompiling ' + grammar_src)):
+            print('\nErrors while recompiling "%s":' % grammar_src +
+                  '\n--------------------------------------\n\n')
+            with open('yaml_ebnf_ERRORS.txt') as f:
+                print(f.read())
+            sys.exit(1)
+
+
+def run_grammar_tests(glob_pattern, get_grammar, get_transformer):
+    with DHParser.log.logging(LOGGING):
+        error_report = testing.grammar_suite(
+            os.path.join(scriptpath, 'grammar_tests'),
+            get_grammar, get_transformer,
+            fn_patterns=[glob_pattern], report=True, verbose=True)
+    return error_report
+
+
+if __name__ == '__main__':
+    argv = sys.argv[:]
+    if len(argv) > 1 and sys.argv[1] == "--debug":
+        LOGGING = True
+        del argv[1]
+    if (len(argv) >= 2 and (argv[1].endswith('.ebnf') or
+        os.path.splitext(argv[1])[1].lower() in testing.TEST_READERS.keys())):
+        # if called with a single filename that is either an EBNF file or a known
+        # test file type then use the given argument
+        arg = argv[1]
+    else:
+        # otherwise run all tests in the test directory
+        arg = '*_test_*.ini'
+    if arg.endswith('.ebnf'):
+        recompile_grammar(arg, force=True)
+    else:
+        recompile_grammar(os.path.join(scriptpath, 'yaml.ebnf'),
+                          force=False)
+        sys.path.append('.')
+        from yamlCompiler import get_grammar, get_transformer
+        error_report = run_grammar_tests(arg, get_grammar, get_transformer)
+        if error_report:
+            print('\n')
+            print(error_report)
+            sys.exit(1)
+        print('ready.\n')

examples/yaml/yaml.ebnf

+# yaml-grammar  see: https://yaml.org/spec/1.2/spec.html
+
+#######################################################################
+#
+#  EBNF-Directives
+#
+#######################################################################
+
+@ whitespace  = vertical        # implicit whitespace, includes any number of line feeds
+@ literalws   = right           # literals have implicit whitespace on the right hand side
+@ comment     = /(?:\/\/|#).*/  # comments range from a '#' odr '//' sign to the end of the line
+@ ignorecase  = False           # literals and regular expressions are case-sensitive
+@ drop        = whitespace, token  # drop tokens and whitespace
+
+
+#######################################################################
+#
+#:  JSON elements
+#
+#######################################################################
+
+json       = ~ element EOF
+element    = value
+value      = object | array | string | number | bool | null
+object     = "{" [member { "," member }] "}"
+member     = string ":" element
+array      = "[" [value { "," value }] "]"
+string     = `"` CHARACTERS `"` ~
+number     = INT FRAC EXP ~
+bool       = /true/~ | /false/~  # use regexes so values are not dropped as tokens
+null       = "null"
+
+#######################################################################
+#
+#:  JSON primitives
+#
+#######################################################################
+
+CHARACTERS = { /[^"\\]+/ | ESCAPE }
+ESCAPE     = /\\[\/bnrt\\]/ | /\\u/ HEX HEX HEX HEX
+HEX        = /[0-9a-fA-F]/
+
+INT        = [`-`] /[0-9]/ | /[1-9][0-9]+/
+FRAC       = [ `.` /[0-9]+/ ]
+EXP        = [ (`E`|`e`) [`+`|`-`] /[0-9]+/ ]
+
+EOF      =  !/./        # no more characters ahead, end of file reached
+