eric: comparison src/eric7/DebugClients/Python/coverage/templite.py

-:3fc8dfeb6ebe
+:b99e7fd55fd3
+# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
+# For details: https://github.com/nedbat/coveragepy/blob/master/NOTICE.txt
+"""A simple Python template renderer, for a nano-subset of Django syntax.
+For a detailed discussion of this code, see this chapter from 500 Lines:
+http://aosabook.org/en/500L/a-template-engine.html
+"""
+# Coincidentally named the same as http://code.activestate.com/recipes/496702/
+import re
+class TempliteSyntaxError(ValueError):
+"""Raised when a template has a syntax error."""
+pass
+class TempliteValueError(ValueError):
+"""Raised when an expression won't evaluate in a template."""
+pass
+class CodeBuilder:
+"""Build source code conveniently."""
+def __init__(self, indent=0):
+self.code = []
+self.indent_level = indent
+def __str__(self):
+return "".join(str(c) for c in self.code)
+def add_line(self, line):
+"""Add a line of source to the code.
+Indentation and newline will be added for you, don't provide them.
+"""
+self.code.extend([" " * self.indent_level, line, "\n"])
+def add_section(self):
+"""Add a section, a sub-CodeBuilder."""
+section = CodeBuilder(self.indent_level)
+self.code.append(section)
+return section
+INDENT_STEP = 4      # PEP8 says so!
+def indent(self):
+"""Increase the current indent for following lines."""
+self.indent_level += self.INDENT_STEP
+def dedent(self):
+"""Decrease the current indent for following lines."""
+self.indent_level -= self.INDENT_STEP
+def get_globals(self):
+"""Execute the code, and return a dict of globals it defines."""
+# A check that the caller really finished all the blocks they started.
+assert self.indent_level == 0
+# Get the Python source as a single string.
+python_source = str(self)
+# Execute the source, defining globals, and return them.
+global_namespace = {}
+exec(python_source, global_namespace)
+return global_namespace
+class Templite:
+"""A simple template renderer, for a nano-subset of Django syntax.
+Supported constructs are extended variable access::
+{{var.modifier.modifier|filter|filter}}
+loops::
+{% for var in list %}...{% endfor %}
+and ifs::
+{% if var %}...{% endif %}
+Comments are within curly-hash markers::
+{# This will be ignored #}
+Lines between `{% joined %}` and `{% endjoined %}` will have lines stripped
+and joined.  Be careful, this could join words together!
+Any of these constructs can have a hyphen at the end (`-}}`, `-%}`, `-#}`),
+which will collapse the whitespace following the tag.
+Construct a Templite with the template text, then use `render` against a
+dictionary context to create a finished string::
+templite = Templite('''
+<h1>Hello {{name|upper}}!</h1>
+{% for topic in topics %}
+<p>You are interested in {{topic}}.</p>
+{% endif %}
+''',
+{'upper': str.upper},
+)
+text = templite.render({
+'name': "Ned",
+'topics': ['Python', 'Geometry', 'Juggling'],
+})
+"""
+def __init__(self, text, *contexts):
+"""Construct a Templite with the given `text`.
+`contexts` are dictionaries of values to use for future renderings.
+These are good for filters and global values.
+"""
+self.context = {}
+for context in contexts:
+self.context.update(context)
+self.all_vars = set()
+self.loop_vars = set()
+# We construct a function in source form, then compile it and hold onto
+# it, and execute it to render the template.
+code = CodeBuilder()
+code.add_line("def render_function(context, do_dots):")
+code.indent()
+vars_code = code.add_section()
+code.add_line("result = []")
+code.add_line("append_result = result.append")
+code.add_line("extend_result = result.extend")
+code.add_line("to_str = str")
+buffered = []
+def flush_output():
+"""Force `buffered` to the code builder."""
+if len(buffered) == 1:
+code.add_line("append_result(%s)" % buffered[0])
+elif len(buffered) > 1:
+code.add_line("extend_result([%s])" % ", ".join(buffered))
+del buffered[:]
+ops_stack = []
+# Split the text to form a list of tokens.
+tokens = re.split(r"(?s)({{.*?}}|{%.*?%}|{#.*?#})", text)
+squash = in_joined = False
+for token in tokens:
+if token.startswith('{'):
+start, end = 2, -2
+squash = (token[-3] == '-')
+if squash:
+end = -3
+if token.startswith('{#'):
+# Comment: ignore it and move on.
+continue
+elif token.startswith('{{'):
+# An expression to evaluate.
+expr = self._expr_code(token[start:end].strip())
+buffered.append("to_str(%s)" % expr)
+else:
+# token.startswith('{%')
+# Action tag: split into words and parse further.
+flush_output()
+words = token[start:end].strip().split()
+if words[0] == 'if':
+# An if statement: evaluate the expression to determine if.
+if len(words) != 2:
+self._syntax_error("Don't understand if", token)
+ops_stack.append('if')
+code.add_line("if %s:" % self._expr_code(words[1]))
+code.indent()
+elif words[0] == 'for':
+# A loop: iterate over expression result.
+if len(words) != 4 or words[2] != 'in':
+self._syntax_error("Don't understand for", token)
+ops_stack.append('for')
+self._variable(words[1], self.loop_vars)
+code.add_line(
+"for c_{} in {}:".format(
+words[1],
+self._expr_code(words[3])
+)
+)
+code.indent()
+elif words[0] == 'joined':
+ops_stack.append('joined')
+in_joined = True
+elif words[0].startswith('end'):
+# Endsomething.  Pop the ops stack.
+if len(words) != 1:
+self._syntax_error("Don't understand end", token)
+end_what = words[0][3:]
+if not ops_stack:
+self._syntax_error("Too many ends", token)
+start_what = ops_stack.pop()
+if start_what != end_what:
+self._syntax_error("Mismatched end tag", end_what)
+if end_what == 'joined':
+in_joined = False
+else:
+code.dedent()
+else:
+self._syntax_error("Don't understand tag", words[0])
+else:
+# Literal content.  If it isn't empty, output it.
+if in_joined:
+token = re.sub(r"\s*\n\s*", "", token.strip())
+elif squash:
+token = token.lstrip()
+if token:
+buffered.append(repr(token))
+if ops_stack:
+self._syntax_error("Unmatched action tag", ops_stack[-1])
+flush_output()
+for var_name in self.all_vars - self.loop_vars:
+vars_code.add_line(f"c_{var_name} = context[{var_name!r}]")
+code.add_line('return "".join(result)')
+code.dedent()
+self._render_function = code.get_globals()['render_function']
+def _expr_code(self, expr):
+"""Generate a Python expression for `expr`."""
+if "|" in expr:
+pipes = expr.split("|")
+code = self._expr_code(pipes[0])
+for func in pipes[1:]:
+self._variable(func, self.all_vars)
+code = f"c_{func}({code})"
+elif "." in expr:
+dots = expr.split(".")
+code = self._expr_code(dots[0])
+args = ", ".join(repr(d) for d in dots[1:])
+code = f"do_dots({code}, {args})"
+else:
+self._variable(expr, self.all_vars)
+code = "c_%s" % expr
+return code
+def _syntax_error(self, msg, thing):
+"""Raise a syntax error using `msg`, and showing `thing`."""
+raise TempliteSyntaxError(f"{msg}: {thing!r}")
+def _variable(self, name, vars_set):
+"""Track that `name` is used as a variable.
+Adds the name to `vars_set`, a set of variable names.
+Raises an syntax error if `name` is not a valid name.
+"""
+if not re.match(r"[_a-zA-Z][_a-zA-Z0-9]*$", name):
+self._syntax_error("Not a valid name", name)
+vars_set.add(name)
+def render(self, context=None):
+"""Render this template by applying it to `context`.
+`context` is a dictionary of values to use in this rendering.
+"""
+# Make the complete context we'll use.
+render_context = dict(self.context)
+if context:
+render_context.update(context)
+return self._render_function(render_context, self._do_dots)
+def _do_dots(self, value, *dots):
+"""Evaluate dotted expressions at run-time."""
+for dot in dots:
+try:
+value = getattr(value, dot)
+except AttributeError:
+try:
+value = value[dot]
+except (TypeError, KeyError) as exc:
+raise TempliteValueError(
+f"Couldn't evaluate {value!r}.{dot}"
+) from exc
+if callable(value):
+value = value()
+return value

Mercurial Repositories > eric / file comparison

comparison: src/eric7/DebugClients/Python/coverage/templite.py

src/eric7/DebugClients/Python/coverage/templite.py