# -*- coding: utf-8 -*-
# cython: language_level=3, always_allow_keywords=True
## Copyright 1999-2025 by LivingLogic AG, Bayreuth/Germany
## Copyright 1999-2025 by Walter Dörwald
##
## All Rights Reserved
##
## See ll/xist/__init__.py for the license
'''
This module is an XIST namespace. It provides a simple template language
based on processing instructions embedded in XML or plain text.
The following example is a simple "Hello, World" type template::
from ll.xist.ns import detox
template = """
<?def helloworld(n=10)?>
<?for i in range(n)?>
Hello, World!
<?end for?>
<?end def?>
"""
module = detox.xml2mod(template)
print "".join(module.helloworld())
'''
import sys, os, datetime, types
from ll import misc
from ll.xist import xsc
__docformat__ = "reStructuredText"
[docs]
class expr(xsc.ProcInst):
"""
Embed the value of the expression
"""
class textexpr(xsc.ProcInst):
pass
class attrexpr(xsc.ProcInst):
pass
[docs]
class code(xsc.ProcInst):
"""
Embed the PI data literally in the generated code.
For example ``<?code foo = 42?>`` will put the statement ``foo = 42`` into
the generated Python source.
"""
[docs]
class if_(xsc.ProcInst):
"""
Starts an if block. An if block can contain zero or more :class:`elif_`
blocks, followed by zero or one :class:`else_` block and must be closed
with an :class:`end` PI.
For example::
<?code import random?>
<?code n = random.choice("123?")?>
<?if n == "1"?>
One
<?elif n == "2"?>
Two
<?elif n == "3"?>
Three
<?else?>
Something else
<?end if?>
"""
xmlname = "if"
[docs]
class elif_(xsc.ProcInst):
"""
Starts an elif block.
"""
xmlname = "elif"
[docs]
class else_(xsc.ProcInst):
"""
Starts an else block.
"""
xmlname = "else"
[docs]
class def_(xsc.ProcInst):
"""
Start a function (or method) definition. A function definition must be
closed with an :class:`end` PI.
Example::
<?def persontable(persons)?>
<table>
<tr>
<th>first name</th>
<th>last name</th>
</tr>
<?for person in persons?>
<tr>
<td><?textexpr person.firstname?></td>
<td><?textexpr person.lastname?></td>
</tr>
<?end for?>
</table>
<?end def?>
If the generated function contains output (i.e. if there is text content
or :class:`expr`, :class:`textexpr` or :class:`attrexpr` PIs before the
matching :class:`end`) the generated function will be a generator function.
Output outside of a function definition will be ignored.
"""
xmlname = "def"
[docs]
class class_(xsc.ProcInst):
"""
Start a class definition. A class definition must be closed with an
:class:`end` PI.
Example::
<?class mylist(list)?>
<?def output(self)?>
<ul>
<?for item in self?>
<li><?textexpr item?></li>
<?endfor?>
</ul>
<?end def?>
<?end class?>
"""
xmlname = "class"
[docs]
class for_(xsc.ProcInst):
"""
Start a ``for`` loop. A for loop must be closed with an :class:`end` PI.
For example::
<ul>
<?for i in range(10)?>
<li><?expr str(i)?></li>
<?end for?>
</ul>
"""
xmlname = "for"
[docs]
class while_(xsc.ProcInst):
"""
Start a ``while`` loop. A while loop must be closed with an :class:`end` PI.
For example::
<?code i = 0?>
<ul>
<?while True?>
<li><?expr str(i)?><?code i += 1?></li>
<?code if i > 10: break?>
<?end while?>
</ul>
"""
xmlname = "while"
[docs]
class end(xsc.ProcInst):
"""
Ends a :class:`while_` or :class:`for_` loop or a :class:`if_`, :class:`def_`
or :class:`class_` block.
"""
# The name of all available processing instructions
targets = {value.xmlname for value in vars().values() if isinstance(value, xsc._ProcInst_Meta)}
# Used for indenting Python source code
indent = "\t"
def xml2py(source):
stack = []
stackoutput = [] # stack containing only True for def and False for class
lines = [
f"# generated by {__file__} on {datetime.datetime.utcnow()} UTC",
"",
"from ll.misc import xmlescape as __detox_xmlescape__",
"",
]
def endscope(action):
if not stack:
raise SyntaxError(f"can't end {action or 'unnamed'} scope: no active scope")
if action and action != stack[-1][0]:
raise SyntaxError(f"can't end {action} scope: active scope is: {stack[-1][0]} {stack[-1][1]}")
return stack.pop()
for (t, s) in misc.tokenizepi(source):
if t is None:
# ignore output outside of functions
if stackoutput and stackoutput[-1]:
lines.append(f"{len(stack)*indent}yield {s!r}")
elif t == "expr":
# ignore output outside of functions
if stackoutput and stackoutput[-1]:
lines.append(f"{len(stack)*indent}yield {s}")
elif t == "textexpr":
# ignore output outside of functions
if stackoutput and stackoutput[-1]:
lines.append(f"{len(stack)*indent}yield __detox_xmlescape__({s})")
elif t == "attrexpr":
# ignore output outside of functions
if stackoutput and stackoutput[-1]:
lines.append(f"{len(stack)*indent}yield __detox_xmlescape__({s})")
elif t == "code":
lines.append(f"{len(stack)*indent}{s}")
elif t == "def":
lines.append("")
lines.append(f"{len(stack)*indent}def {s}:")
stack.append((t, s))
stackoutput.append(True)
elif t == "class":
lines.append("")
lines.append(f"{len(stack)*indent}class {s}:")
stack.append((t, s))
stackoutput.append(False)
elif t == "for":
lines.append(f"{len(stack)*indent}for {s}:")
stack.append((t, s))
elif t == "while":
lines.append(f"{len(stack)*indent}while {s}:")
stack.append((t, s))
elif t == "if":
lines.append(f"{len(stack)*indent}if {s}:")
stack.append((t, s))
elif t == "else":
lines.append(f"{(len(stack)-1)*indent}else:")
elif t == "elif":
lines.append(f"{(len(stack)-1)*indent}elif {s}:")
elif t == "end":
scope = endscope(s)
if scope in ("def", "class"):
stackoutput.pop()
else: # unknown PI target => treat as text
# ignore output outside of functions
if stackoutput and stackoutput[-1]:
s = f"<?{t} {s}?>"
lines.append(f"{len(stack)*indent}yield {s!r}")
if stack:
scopes = ", ".join(scope[0] for scope in stack)
raise SyntaxError(f"unclosed scopes remaining: {scopes}")
return "\n".join(lines)
def xml2mod(source, name=None, filename="unnamed.py"):
return misc.module(xml2py(source), filename, name)
# The following stuff has been copied from Kids import hook
DETOX_EXT = ".detox"
def enable_import(suffixes=None):
class DetoxLoader:
def __init__(self, path=None):
if path and os.path.isdir(path):
self.path = path
else:
raise ImportError
def find_module(self, fullname):
path = os.path.join(self.path, fullname.split(".")[-1])
for ext in [cls.DETOX_EXT] + self.suffixes:
if os.path.exists(path + ext):
self.filename = path + ext
return self
return None
def load_module(self, fullname):
try:
return sys.modules[fullname]
except KeyError:
return xml2mod(open(self.filename, "r").read(), name=fullname, filename=self.filename, store=True, loader=self)
DetoxLoader.suffixes = suffixes or []
sys.path_hooks.append(DetoxLoader)
sys.path_importer_cache.clear()