Templating In Python

This was a quick, quick hack, because I got tired of having to do math when I move things in my mutator config or add elements. Just save the program text at the end to template.py, or whatever else you'd rather call it. It's a simple preprocessor which will generate new files from template files given on the command line. Any file specified will have its extension stripped to produce the name for the new file. Directories specified will be searched recursively for .template files, which will be processed into new files without the .template extension. Basically, it makes a clean environment for each file, in which commands embedded in the file can be executed. Anything between two lines starting with "!!exec" will be executed, but will produce no output in the processed file. Anything between a pair of "!!" on a line will be evaluated as an expression in Python, and will have its value converted to a string and inserted in place of the expression. The exec block feature is mostly for setting up constants. Also, you can change the formatting used for expression which yield floating-point values by setting "floatformat" to a Python format string in an exec block. Here's a quick sample, from some of the code I'm actually using this with (cut down a little bit):

This is part of RadarConfig.uc.template:

!!exec set up constants for GUI layout
gridw=21.0
gridh=19.0
llbll=1.0
nmlblw=4.0
elh=2.0
row1t=1.0
row2t=4.0
floatformat="%0.8f"
!!exec
defaultproperties
{
    Begin Object Class=GUIButton name=DialogBackground
        WinWidth=1.0
        WinHeight=1.0
        WinTop=0
        WinLeft=0
        bAcceptsInput=false
        bNeverFocus=true
        StyleName="ComboListBox"
        bBoundToParent=True
        bScaleToParent=True
    End Object
    Controls(0)=GUIButton'TacticalDisplay.RadarConfig.DialogBackground'
    Begin Object Class=GUILabel name=DialogText
        Caption="Tactical Display Configuration"
        TextAlign=TXTA_Center
        WinWidth=1.0
        WinHeight=!!elh/gridh!!
        WinLeft=0.0
        WinTop=!!row1t/gridh!!
        bBoundToParent=True
        bScaleToParent=True
    End Object
    Controls(1)=GUILabel'TacticalDisplay.RadarConfig.DialogText'
    Begin Object Class=GUILabel name=DetectRangeText
        Caption="Maximum Range"
        WinWidth=!!nmlblw/gridw!!
        WinHeight=!!elh/gridh!!
        WinLeft=!!llbll/gridw!!
        WinTop=!!row2t/gridh!!
        bBoundToParent=True
        bScaleToParent=True
    End Object
    Controls(2)=GUILabel'TacticalDisplay.RadarConfig.DetectRangeText'

Running template.py on it generates this:

defaultproperties
{
    Begin Object Class=GUIButton name=DialogBackground
        WinWidth=1.0
        WinHeight=1.0
        WinTop=0
        WinLeft=0
        bAcceptsInput=false
        bNeverFocus=true
        StyleName="ComboListBox"
        bBoundToParent=True
        bScaleToParent=True
    End Object
    Controls(0)=GUIButton'TacticalDisplay.RadarConfig.DialogBackground'
    Begin Object Class=GUILabel name=DialogText
        Caption="Tactical Display Configuration"
        TextAlign=TXTA_Center
        WinWidth=1.0
        WinHeight=0.10526316
        WinLeft=0.0
        WinTop=0.05263158
        bBoundToParent=True
        bScaleToParent=True
    End Object
    Controls(1)=GUILabel'TacticalDisplay.RadarConfig.DialogText'
    Begin Object Class=GUILabel name=DetectRangeText
        Caption="Maximum Range"
        WinWidth=0.19047619
        WinHeight=0.10526316
        WinLeft=0.04761905
        WinTop=0.21052632
        bBoundToParent=True
        bScaleToParent=True
    End Object
    Controls(2)=GUILabel'TacticalDisplay.RadarConfig.DetectRangeText'

I've deleted the rest of the controls (there are 26 in this dialog), and the constants that are associated with them, but you get the idea. to add a new control at the bottom of the dialog, for example, I can make some new constants to define its location, and change gridh, then rerun template.py.

And finally, here's the Python script:

#!/usr/bin/python

import os, sys, re, types

evalre = re.compile('!!(.*?)!!')

def visitor (arg, dirname, names):
    for filename in names:
        if filename[-9:] == ".template":
            processfile(os.path.join(dirname,filename))

def processfile(filename):
    envlocals={}
    envglobals={}
    execstring=""
    inexec=0
    infile=file(filename,"r")
    outfile=file(os.path.splitext(filename)[0],"w")
    for line in infile.xreadlines():
        if line[:6]=="!!exec":
            if inexec:
                exec(execstring,envglobals,envlocals)
                execstring=""
                inexec=0
            else:
                inexec=1
                
            continue
        if inexec:
            execstring += line
            continue
        index = 0
        newline = ""
        match = evalre.search(line,index)
        while match:
            val = eval(match.group(1),envglobals,envlocals)
            if type(val) == types.FloatType and envlocals.has_key("floatformat"):
                val = envlocals["floatformat"] % val
            else:
                val = str(val)
            newline += line[index:match.start()]
            newline += val
            index = match.end()
            match = evalre.search(line,index)
        newline += line[index:]
        outfile.write(newline)
        infile.close
        outfile.close

for filename in sys.argv[1:]:
    if os.path.exists(filename):
        if os.path.isdir(filename):
            os.path.walk(filename,visitor,None)
        elif os.path.isfile(filename):
            processfile(filename)

In case your browse messes up the whitespace, you can also get the [script in a file].

Templating In Python

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