translate s-expressions to tk/wish scripts.

sxp2tk.py

#! /usr/bin/python

# This script translates s-expressions (ie. the Lisp/Scheme data notation)
# into tk scripts with nested widgets.  Example input:
#
# ;; --*-scheme-*--
# (frame
#  :grid v
#  (frame
#   :grid h
#   (label :-text "File: ")
#   (label :-textvariable "filename"))
#  (frame
#   :grid h
#   (label :-text "Comment: ")
#   (entry :-width 80 :-textvariable "comment"))
#  (frame
#   :grid h
#   (button :-text "OK" :-command "echo_comment_and_exit")
#   (button :-text "Cancel" :-command "exit 1")))
#
# This produces the following output:
#
# frame .g__0
# grid .g__0 -column 0 -row 0
# frame .g__0.g__1
# grid .g__0.g__1 -column 0 -row 0
# frame .g__0.g__2
# grid .g__0.g__2 -column 0 -row 1
# frame .g__0.g__3
# grid .g__0.g__3 -column 0 -row 2
# label .g__0.g__1.g__4 -text "File: "
# grid .g__0.g__1.g__4 -column 0 -row 0
# label .g__0.g__1.g__5 -textvariable "filename"
# grid .g__0.g__1.g__5 -column 1 -row 0
# label .g__0.g__2.g__6 -text "Comment: "
# grid .g__0.g__2.g__6 -column 0 -row 0
# entry .g__0.g__2.g__7 -width "80" -textvariable "comment"
# grid .g__0.g__2.g__7 -column 1 -row 0
# button .g__0.g__3.g__8 -command "echo_comment_and_exit" -text "OK"
# grid .g__0.g__3.g__8 -column 0 -row 0
# button .g__0.g__3.g__9 -command "exit 1" -text "Cancel"
# grid .g__0.g__3.g__9 -column 1 -row 0

import sexpdata as SE
import sys
from Queue import Queue
from argparse import ArgumentParser


VAR_FORMAT = '''set {n} "{v}"

proc echo_{n} {{}} {{
    puts $::{n}
}}

proc echo_{n}_and_exit {{}} {{
    puts $::{n}
    exit 0
}}

'''

class InvalidSpecError(Exception):
    pass

def gensym():
    g = 0
    while True:
        yield ('g__%s' % g)
        g += 1

Gensym = gensym()

def generate_subdata(iterable):
    iterator = iterable.__iter__()
    pair_valid = True
    val = None
    ungot = None
    try:
        while True:
            item = ungot or iterator.next()
            ungot = None
            if isinstance(item, list):
                yield item
                val = None
                pair_valid = False
            elif isinstance(item, SE.Symbol):
                val = item._val
                if not pair_valid:
                    raise InvalidSpecError('symbol after sublist: %s' % val)
                item = iterator.next()
                if isinstance(item, list):
                    yield (val, True)
                    val = None
                    ungot = item
                else:
                    yield (val, item)
                    val = None
    except StopIteration:
        if val is not None:
            yield (val, True)

def data2tk(data, parent, gridtype, gridindex, io):
    if not isinstance(data[0], SE.Symbol):
        raise InvalidSpecError('constructor is not a symbol: %s' % data[0])
    constructor = data[0]._val
    tk_attribs = {}
    x_attribs = {}
    kids = []
    for sd in generate_subdata(data[1:]):
        if isinstance(sd, tuple):
            k, v = sd
            if isinstance(v, SE.Symbol):
                v = v._val
            if k.startswith(':-'):
                tk_attribs[k[1:]] = v
            elif k.startswith(':'):
                x_attribs[k[1:]] = v
            else:
                # ignore these for now, perhaps reserve for extension mechanism
                pass
        elif isinstance(sd, list):
            kids.append(sd)
    tkid = '.'.join((parent, Gensym.next()))
    construct_cmd = ' '.join((constructor, tkid))
    for k, v in tk_attribs.items():
        construct_cmd += ' {k} "{v}"'.format(k=k, v=v)
    construct_cmd += '\n'
    io.write(construct_cmd)
    if gridtype == 'h':
        args = {'i': tkid, 'c': gridindex, 'r': 0}
    elif gridtype == 'v':
        args = {'i': tkid, 'c': 0, 'r': gridindex}
    else:
        args = {'i': tkid, 'c': 0, 'r': 0}
    io.write('grid {i} -column {c} -row {r}\n'.format(**args))
    if 'obvar' in x_attribs:
        io.write('set {o} "{i}"\n'.format(o=x_attribs['obvar'], i=tkid))
    kg = x_attribs.get('grid', None)
    return enumerate([(k, tkid, kg) for k in kids])

def process_var(outstr, variable):
    if not '=' in variable:
        n = variable
        v = ''
    else:
        n, v = variable.split('=', 1)
    outstr.write(VAR_FORMAT.format(n=n, v=v))

def process_spec(instr, outstr, title, variables):
    if title is not None:
        outstr.write('wm title . "{t}"\n'.format(t=title))
    for v in variables:
        process_var(outstr, v)
    data = SE.load(instr)
    q = Queue()
    e = data2tk(data, '', None, 0, outstr)
    for k in e:
        q.put(k)
    while not q.empty():
        gi, tp = q.get()
        k, tkid, kg = tp
        e = data2tk(k, tkid, kg, gi, outstr)
        for k in e:
            q.put(k)

def main():
    ap = ArgumentParser(description='Translate sexp notation into wish script.')
    ap.add_argument('-o', '--outfile', help='write to OUTFILE not stdout')
    ap.add_argument('-T', '--title', help='give TITLE to toplevel window')
    ap.add_argument('-v', '--var', action='append', default=[],
                    help='declare and set VAR [format: NAME=VALUE]')
    ap.add_argument('infile', nargs='?', help='read from INFILE not stdin')
    args = ap.parse_args()
    with open(args.outfile or '/dev/stdout', 'w') as outstr:
        with open(args.infile or '/dev/stdin') as instr:
            process_spec(instr, outstr, args.title, args.var)


if __name__ == "__main__":
    main()