8c5a69eb47
The List and Dict types are no longer implicitly available. They must be imported from typing. Type annotations must appear before the doc comment in a function. Also fix type errors in these functions that weren't detected before.
139 lines
3.6 KiB
Python
139 lines
3.6 KiB
Python
"""
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Source code generator.
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The `srcgen` module contains generic helper routines and classes for generating
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source code.
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"""
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from __future__ import absolute_import
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import sys
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import os
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import re
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try:
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from typing import Any, List # noqa
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except ImportError:
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pass
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class Formatter(object):
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"""
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Source code formatter class.
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- Collect source code to be written to a file.
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- Keep track of indentation.
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Indentation example:
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>>> f = Formatter()
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>>> f.line('Hello line 1')
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>>> f.writelines()
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Hello line 1
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>>> f.indent_push()
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>>> f.comment('Nested comment')
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>>> f.indent_pop()
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>>> f.format('Back {} again', 'home')
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>>> f.writelines()
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Hello line 1
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// Nested comment
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Back home again
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"""
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shiftwidth = 4
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def __init__(self):
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# type: () -> None
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self.indent = ''
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self.lines = [] # type: List[str]
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def indent_push(self):
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# type: () -> None
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"""Increase current indentation level by one."""
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self.indent += ' ' * self.shiftwidth
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def indent_pop(self):
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# type: () -> None
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"""Decrease indentation by one level."""
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assert self.indent != '', 'Already at top level indentation'
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self.indent = self.indent[0:-self.shiftwidth]
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def line(self, s=None):
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# type: (str) -> None
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"""Add an indented line."""
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if s:
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self.lines.append('{}{}\n'.format(self.indent, s))
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else:
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self.lines.append('\n')
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def outdented_line(self, s):
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# type: (str) -> None
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"""
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Emit a line outdented one level.
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This is used for '} else {' and similar things inside a single indented
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block.
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"""
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self.lines.append('{}{}\n'.format(self.indent[0:-self.shiftwidth], s))
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def writelines(self, f=None):
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# type: (Any) -> None
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"""Write all lines to `f`."""
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if not f:
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f = sys.stdout
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f.writelines(self.lines)
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def update_file(self, filename, directory):
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# type: (str, str) -> None
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if directory is not None:
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filename = os.path.join(directory, filename)
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with open(filename, 'w') as f:
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self.writelines(f)
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class _IndentedScope(object):
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def __init__(self, fmt, after):
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# type: (Formatter, str) -> None
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self.fmt = fmt
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self.after = after
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def __enter__(self):
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# type: () -> None
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self.fmt.indent_push()
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def __exit__(self, t, v, tb):
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self.fmt.indent_pop()
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if self.after:
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self.fmt.line(self.after)
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def indented(self, before=None, after=None):
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# type: (str, str) -> Formatter._IndentedScope
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"""
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Return a scope object for use with a `with` statement:
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>>> f = Formatter()
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>>> with f.indented('prefix {', '} suffix'):
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... f.line('hello')
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>>> f.writelines()
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prefix {
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hello
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} suffix
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The optional `before` and `after` parameters are surrounding lines
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which are *not* indented.
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"""
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if before:
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self.line(before)
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return Formatter._IndentedScope(self, after)
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def format(self, fmt, *args):
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self.line(fmt.format(*args))
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def comment(self, s):
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"""Add a comment line."""
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self.line('// ' + s)
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def doc_comment(self, s):
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"""Add a (multi-line) documentation comment."""
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s = re.sub('^', self.indent + '/// ', s, flags=re.M) + '\n'
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self.lines.append(s)
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