dsl.py 17 KB
Newer Older
1
"""dsl.py - Support for domain specific notations for DHParser
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21

Copyright 2016  by Eckhart Arnold (arnold@badw.de)
                Bavarian Academy of Sciences an Humanities (badw.de)

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

    http://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.

Module ``DSLsupport`` contains various functions to support the
compilation of domain specific languages based on an EBNF-grammar.
"""

di68kap's avatar
di68kap committed
22
import collections
23
import os
24

25
26
27
28
29
try:
    import regex as re
except ImportError:
    import re

30
from .ebnf import EBNFGrammar, EBNFTransformer, EBNFCompiler, grammar_changed, \
31
    get_ebnf_scanner, get_ebnf_grammar, get_ebnf_transformer, get_ebnf_compiler
Eckhart Arnold's avatar
Eckhart Arnold committed
32
33
from .toolkit import logging, load_if_file, is_python_code, compile_python_object
from .parsers import GrammarBase, CompilerBase, compile_source, nil_scanner
34
from .syntaxtree import Node
35

Eckhart Arnold's avatar
Eckhart Arnold committed
36
37
38
39
40

__all__ = ['GrammarError',
           'CompilationError',
           'load_compiler_suite',
           'compileDSL',
41
42
           'compileEBNF',
           'compile_parser',
43
           'compile_on_disk']
Eckhart Arnold's avatar
Eckhart Arnold committed
44
45


46
47
48
49
50
51
52
53
54
SECTION_MARKER = """\n
#######################################################################
#
# {marker}
#
#######################################################################
\n"""

RX_SECTION_MARKER = re.compile(SECTION_MARKER.format(marker=r'.*?SECTION.*?'))
55
RX_WHITESPACE = re.compile('\s*')
56
57
58
59
60
61

SYMBOLS_SECTION = "SYMBOLS SECTION - Can be edited. Changes will be preserved."
SCANNER_SECTION = "SCANNER SECTION - Can be edited. Changes will be preserved."
PARSER_SECTION = "PARSER SECTION - Don't edit! CHANGES WILL BE OVERWRITTEN!"
AST_SECTION = "AST SECTION - Can be edited. Changes will be preserved."
COMPILER_SECTION = "COMPILER SECTION - Can be edited. Changes will be preserved."
di68kap's avatar
di68kap committed
62
END_SECTIONS_MARKER = "END OF DHPARSER-SECTIONS"
63
64


65
DHPARSER_IMPORTS = '''
di68kap's avatar
di68kap committed
66
from functools import partial
Eckhart Arnold's avatar
Eckhart Arnold committed
67
import os
68
import sys
di68kap's avatar
di68kap committed
69
70
71
72
try:
    import regex as re
except ImportError:
    import re
Eckhart Arnold's avatar
Eckhart Arnold committed
73
from DHParser.toolkit import logging, is_filename, load_if_file    
74
from DHParser.parsers import GrammarBase, CompilerBase, nil_scanner, \\
di68kap's avatar
di68kap committed
75
76
    Lookbehind, Lookahead, Alternative, Pop, Required, Token, \\
    Optional, NegativeLookbehind, OneOrMore, RegExp, Retrieve, Sequence, RE, Capture, \\
Eckhart Arnold's avatar
Eckhart Arnold committed
77
    ZeroOrMore, Forward, NegativeLookahead, mixin_comment, compile_source
78
79
80
81
from DHParser.syntaxtree import Node, traverse, remove_enclosing_delimiters, \\
    remove_children_if, reduce_single_child, replace_by_single_child, remove_whitespace, \\
    no_operation, remove_expendables, remove_tokens, flatten, is_whitespace, is_expendable, \\
    WHITESPACE_KEYWORD, TOKEN_KEYWORD
82
'''
di68kap's avatar
di68kap committed
83

84

Eckhart Arnold's avatar
Eckhart Arnold committed
85
DHPARSER_MAIN = '''
86
87
88
def compile_{NAME}(source):
    """Compiles ``source`` and returns (result, errors, ast).
    """
Eckhart Arnold's avatar
Eckhart Arnold committed
89
    with logging("LOGS"):
Eckhart Arnold's avatar
Eckhart Arnold committed
90
        compiler = get_{NAME}_compiler()
Eckhart Arnold's avatar
Eckhart Arnold committed
91
92
93
        cname = compiler.__class__.__name__
        log_file_name = os.path.basename(os.path.splitext(source)[0]) \\
            if is_filename(source) < 0 else cname[:cname.find('.')] + '_out'    
Eckhart Arnold's avatar
Eckhart Arnold committed
94
95
96
        result = compile_source(source, get_{NAME}_scanner(), 
                                get_{NAME}_grammar(),
                                get_{NAME}_transformer(), compiler)
Eckhart Arnold's avatar
Eckhart Arnold committed
97
98
    return result

99
100
101
102
103
104
105
106
107
108
109
110
111
112

if __name__ == "__main__":
    if len(sys.argv) > 1:
        result, errors, ast = compile_{NAME}(sys.argv[1])
        if errors:
            for error in errors:
                print(error)
                sys.exit(1)
        else:
            print(result)
    else:
        print("Usage: {NAME}_compiler.py [FILENAME]")
'''

113

114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
class GrammarError(Exception):
    """Raised when (already) the grammar of a domain specific language (DSL)
    contains errors.
    """

    def __init__(self, error_messages, grammar_src):
        self.error_messages = error_messages
        self.grammar_src = grammar_src


class CompilationError(Exception):
    """Raised when a string or file in a domain specific language (DSL)
    contains errors.
    """

    def __init__(self, error_messages, dsl_text, dsl_grammar, AST):
        self.error_messages = error_messages
        self.dsl_text = dsl_text
        self.dsl_grammar = dsl_grammar
        self.AST = AST

    def __str__(self):
        return '\n'.join(self.error_messages)


139
def grammar_instance(grammar_representation):
140
141
142
143
144
    """Returns a grammar object and the source code of the grammar, from
    the given `grammar`-data which can be either a file name, ebnf-code,
    python-code, a GrammarBase-derived grammar class or an instance of
    such a class (i.e. a grammar object already).
    """
145
    if isinstance(grammar_representation, str):
146
        # read grammar
147
148
        grammar_src = load_if_file(grammar_representation)
        if is_python_code(grammar_representation):
149
150
            parser_py, errors, AST = grammar_src, '', None
        else:
Eckhart Arnold's avatar
Eckhart Arnold committed
151
152
            with logging(False):
                parser_py, errors, AST = compile_source(grammar_src, None,
Eckhart Arnold's avatar
Eckhart Arnold committed
153
                    get_ebnf_grammar(), get_ebnf_transformer(), get_ebnf_compiler())
154
        if errors:
155
            raise GrammarError('\n\n'.join(errors), grammar_src)
di68kap's avatar
di68kap committed
156
        parser_root = compile_python_object(DHPARSER_IMPORTS + parser_py, '\w*Grammar$')()
157
158
159
    else:
        # assume that dsl_grammar is a ParserHQ-object or Grammar class
        grammar_src = ''
160
161
        if isinstance(grammar_representation, GrammarBase):
            parser_root = grammar_representation
162
        else:
Eckhart Arnold's avatar
Eckhart Arnold committed
163
164
            # assume ``grammar_representation`` is a grammar class and get the root object
            # TODO: further case: grammar_representation is a method
165
            parser_root = grammar_representation()
166
167
168
    return parser_root, grammar_src


169
def compileDSL(text_or_file, scanner, dsl_grammar, ast_transformation, compiler):
170
    """Compiles a text in a domain specific language (DSL) with an
171
172
    EBNF-specified grammar. Returns the compiled text or raises a
    compilation error.
173
174
175
    
    Raises:
        CompilationError if any errors occured during compilation
176
177
178
    """
    assert isinstance(text_or_file, str)
    assert isinstance(compiler, CompilerBase)
Eckhart Arnold's avatar
Eckhart Arnold committed
179

180
    parser_root, grammar_src = grammar_instance(dsl_grammar)
Eckhart Arnold's avatar
Eckhart Arnold committed
181
182
183
184
185
    result, errors, AST = compile_source(text_or_file, scanner, parser_root,
                                         ast_transformation, compiler)
    if errors:
        src = load_if_file(text_or_file)
        raise CompilationError(errors, src, grammar_src, AST)
186
187
188
    return result


189
def compileEBNF(ebnf_src, branding = "DSL"):
190
191
192
    """Compiles an EBNF source file. Either returns a factory function
    for the grammar-paraser or the source code of a compiler suite with
    skeletons for scanner, transformer and compiler.
193
194
195
196

    Args:
        ebnf_src(str):  Either the file name of an EBNF grammar or
            the EBNF grammar itself as a string.
197
198
        branding (str or bool):  Branding name for the compiler
            suite source code. 
199
    Returns:
200
        The complete compiler suite skeleton as Python source code.
201
    """
202
203
204
    grammar = get_ebnf_grammar()
    if branding == True:  branding = "DSL"
    compiler = get_ebnf_compiler(branding or "DSL", ebnf_src)
Eckhart Arnold's avatar
Eckhart Arnold committed
205
    grammar_src = compileDSL(ebnf_src, nil_scanner, grammar, EBNFTransformer, compiler)
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
    src = [DHPARSER_IMPORTS,
           compiler.gen_scanner_skeleton(),
           grammar_src,
           compiler.gen_transformer_skeleton(),
           compiler.gen_compiler_skeleton(),
           DHPARSER_MAIN.format(NAME=branding)]
    return '\n'.join(src)


def compile_parser(ebnf_src, branding="DSL"):
    """Compiles an EBNF grammar and returns a grammar-parser factory
    function for that grammar.

    Args:
        ebnf_src(str):  Either the file name of an EBNF grammar or
            the EBNF grammar itself as a string.
        branding (str or bool):  Branding name for the compiler
            suite source code. 
    
    Returns:
        A factory function for a grammar-parser for texts in the
        language defined by ``ebnf_src``.
    """
    grammar_src = compileDSL(ebnf_src, nil_scanner, get_ebnf_grammar(),
                             get_ebnf_transformer(), get_ebnf_compiler(branding))
    return compile_python_object(DHPARSER_IMPORTS + grammar_src, 'get_\w*_grammar$')
232
233


234
235
236
def load_compiler_suite(compiler_suite):
    """Extracts a compiler suite from file or string ``compiler suite``
    and returns it as a tuple (scanner, parser, ast, compiler).
Eckhart Arnold's avatar
Eckhart Arnold committed
237
238
239
    
    Returns:
        4-tuple (scanner function, parser class, ast transformer function, compiler class)
240
241
242
243
244
245
246
247
248
249
250
    """
    global RX_SECTION_MARKER
    assert isinstance(compiler_suite, str)
    source = load_if_file(compiler_suite)
    if is_python_code(compiler_suite):
        try:
            intro, imports, scanner_py, parser_py, ast_py, compiler_py, outro = \
                RX_SECTION_MARKER.split(source)
        except ValueError as error:
            raise AssertionError('File "' + compiler_suite + '" seems to be corrupted. '
                                 'Please delete or repair file manually.')
251
        # TODO: Compile in one step and pick parts from namespace later ?
252
253
254
        scanner = compile_python_object(imports + scanner_py, 'get_\w*_scanner$')
        ast = compile_python_object(imports + ast_py, 'get_\w*_transformer$')
        compiler = compile_python_object(imports + compiler_py, 'get_\w*_compiler$')
255
256
    else:
        # assume source is an ebnf grammar
Eckhart Arnold's avatar
Eckhart Arnold committed
257
258
259
        with logging(False):
            parser_py, errors, AST = compile_source(source, None,
                get_ebnf_grammar(), get_ebnf_transformer(), get_ebnf_compiler())
260
261
        if errors:
            raise GrammarError('\n\n'.join(errors), source)
262
263
264
265
        scanner = get_ebnf_scanner
        ast = get_ebnf_transformer
        compiler = get_ebnf_compiler
    parser = compile_python_object(DHPARSER_IMPORTS + parser_py, 'get_\w*_grammar$')
266
267
268
269

    return scanner, parser, ast, compiler


Eckhart Arnold's avatar
Eckhart Arnold committed
270
def is_outdated(compiler_suite, grammar_source):
271
272
273
274
275
276
277
278
    """Returns ``True``  if the ``compile_suite`` needs to be updated.
     
    An update is needed, if either the grammar in the compieler suite 
    does not reflect the latest changes of ``grammar_source`` or if 
    sections from the compiler suite have diligently been overwritten
    with whitespace order to trigger their recreation. Note: Do not
    delete or overwrite the section marker itself. 

279
    Args:
280
281
282
283
284
285
286
287
288
289
        compiler_suite:  the parser class representing the grammar
            or the file name of a compiler suite containing the grammar
        grammar_source:  File name or string representation of the
            EBNF code of the grammar

    Returns (bool):
        True, if ``compiler_suite`` seems to be out of date.
    """
    try:
        scanner, grammar, ast, compiler = load_compiler_suite(compiler_suite)
290
        return grammar_changed(grammar(), grammar_source)
291
292
293
294
    except ValueError:
        return True


295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
def run_compiler(text_or_file, compiler_suite):
    """Compiles a source with a given compiler suite.

    Args:
        text_or_file (str):  Either the file name of the source code or
            the source code directly. (Which is determined by 
            heuristics. If ``text_or_file`` contains at least on
            linefeed then it is always assumed to be a source text and
            not a file name.)
        compiler_suite(str):  File name of the compiler suite to be
            used.
        
    Returns:
        The result of the compilation, the form and type of which 
        depends entirely on the compiler.
        
    Raises:
        CompilerError
    """
    scanner, parser, ast, compiler = load_compiler_suite(compiler_suite)
315
    return compileDSL(text_or_file, scanner(), parser(), ast(), compiler())
316
317
318


def compile_on_disk(source_file, compiler_suite="", extension=".xml"):
319
320
321
    """Compiles the a source file with a given compiler and writes the
    result to a file.

Eckhart Arnold's avatar
Eckhart Arnold committed
322
323
324
325
326
327
    If no ``compiler_suite`` is given it is assumed that the source
    file is an EBNF grammar. In this case the result will be a Python
    script containing a parser for that grammar as well as the
    skeletons for a scanner, AST transformation table, and compiler.
    If the Python script already exists only the parser name in the
    script will be updated. (For this to work, the different names
328
    need to be delimited section marker blocks.). `compile_on_disk()`
Eckhart Arnold's avatar
Eckhart Arnold committed
329
330
    returns a list of error messages or an empty list if no errors
    occurred.
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
    
    Parameters:
        source_file(str):  The file name of the source text to be
            compiled.
        compiler_suite(str):  The file name of the compiler suite
            (usually ending with '_compiler.py'), with which the source
            file shall be compiled. If this is left empty, the source
            file is assumed to be an EBNF-Grammar that will be compiled
            with the internal EBNF-Compiler.
        extension(str):  The result of the compilation (if successful)
            is written to a file with the same name but a different
            extension than the source file. This parameter sets the
            extension.
            
    Returns:
        A list of error messages or an empty list if there were no 
        errors. 
Eckhart Arnold's avatar
Eckhart Arnold committed
348
    """
349
    filepath = os.path.normpath(source_file)
350
351
    # with open(source_file, encoding="utf-8") as f:
    #     source = f.read()
352
    rootname = os.path.splitext(filepath)[0]
353
    compiler_name = os.path.basename(rootname)
354
    if compiler_suite:
355
        scanner, parser, trans, cfactory = load_compiler_suite(compiler_suite)
356
    else:
357
358
359
360
361
362
        scanner = get_ebnf_scanner
        parser = get_ebnf_grammar
        trans = get_ebnf_transformer
        cfactory = get_ebnf_compiler
    compiler1 = cfactory(compiler_name, source_file)
    result, errors, ast = compile_source(source_file, scanner(), parser(), trans(), compiler1)
363
364
365
    if errors:
        return errors

366
    elif cfactory == get_ebnf_compiler:  # trans == get_ebnf_transformer or trans == EBNFTransformer:  # either an EBNF- or no compiler suite given
367
        global SECTION_MARKER, RX_SECTION_MARKER, SCANNER_SECTION, PARSER_SECTION, \
Eckhart Arnold's avatar
Eckhart Arnold committed
368
369
            AST_SECTION, COMPILER_SECTION, END_SECTIONS_MARKER, RX_WHITESPACE, \
            DHPARSER_MAIN, DHPARSER_IMPORTS
370
        f = None
371
372
373
        try:
            f = open(rootname + '_compiler.py', 'r', encoding="utf-8")
            source = f.read()
374
375
            sections = RX_SECTION_MARKER.split(source)
            intro, imports, scanner, parser, ast, compiler, outro = sections
376
        except (PermissionError, FileNotFoundError, IOError) as error:
377
            intro, imports, scanner, parser, ast, compiler, outro = '', '', '', '', '', '', ''
378
379
380
381
        except ValueError as error:
            raise ValueError('File "' + rootname + '_compiler.py" seems to be corrupted. '
                                                   'Please delete or repair file manually!')
        finally:
382
383
384
            if f:
                f.close()
                f = None
385

386
387
388
        if RX_WHITESPACE.fullmatch(intro):
            intro = '#!/usr/bin/python'
        if RX_WHITESPACE.fullmatch(outro):
Eckhart Arnold's avatar
Eckhart Arnold committed
389
            outro = DHPARSER_MAIN.format(NAME=compiler_name)
390
391
392
        if RX_WHITESPACE.fullmatch(imports):
            imports = DHPARSER_IMPORTS
        if RX_WHITESPACE.fullmatch(scanner):
393
            scanner = compiler1.gen_scanner_skeleton()
394
        if RX_WHITESPACE.fullmatch(ast):
395
            ast = compiler1.gen_transformer_skeleton()
396
        if RX_WHITESPACE.fullmatch(compiler):
397
            compiler = compiler1.gen_compiler_skeleton()
398

399
400
401
402
        try:
            f = open(rootname + '_compiler.py', 'w', encoding="utf-8")
            f.write(intro)
            f.write(SECTION_MARKER.format(marker=SYMBOLS_SECTION))
403
            f.write(imports)
404
405
406
            f.write(SECTION_MARKER.format(marker=SCANNER_SECTION))
            f.write(scanner)
            f.write(SECTION_MARKER.format(marker=PARSER_SECTION))
407
            f.write(result)
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
            f.write(SECTION_MARKER.format(marker=AST_SECTION))
            f.write(ast)
            f.write(SECTION_MARKER.format(marker=COMPILER_SECTION))
            f.write(compiler)
            f.write(SECTION_MARKER.format(marker=END_SECTIONS_MARKER))
            f.write(outro)
        except (PermissionError, FileNotFoundError, IOError) as error:
            print('# Could not write file "' + rootname + '_compiler.py" because of: '
                  + "\n# ".join(str(error).split('\n)')))
            print(result)
        finally:
            if f:  f.close()

    else:
        try:
            f = open(rootname + extension, 'w', encoding="utf-8")
            if isinstance(result, Node):
                f.write(result.as_xml())
            else:
                f.write(result)
        except (PermissionError, FileNotFoundError, IOError) as error:
            print('# Could not write file "' + rootname + '.py" because of: '
                  + "\n# ".join(str(error).split('\n)')))
            print(result)
        finally:
            if f:  f.close()

    return []