prescad.py

import re

def replace_name_token(t,params_dict):
    if t in params_dict:
        return 'children(%s)' % params_dict[t]
    else:
        return t

token_re_list = [
    ('int', r'(?P<int>[-+]?(0[xX][\dA-Fa-f]+|0[0-7]*|\d+))'),
    ('float', r'(?P<float>[-+]?(\d+(\.\d*)?|\.\d+)([eE][-+]?\d+)?)'),
    ('strdbl', r'(?P<strdbl>["]([^"]|\")*["])'),
    ('strquot', r"(?P<strquot>[']([^']|\')*['])"),
    ('ident', r'(?P<ident>[a-zA-Z_][a-zA-Z0-9_]*)'),
    ('op', r'(?P<op>[-+\*/=!%\^&\(\)\[\]\{\}:;<>,\.\#\$\@\?]+)'),
    ('ws', r'(?P<ws>[ \t\r\n]+)')
]

token_re = dict([(x[0], re.compile(x[1])) for x in token_re_list])

def tokens_of(lineno, line):
    endpos = 0
    while endpos < len(line):
        for p,re in token_re.items():
    	    m = re.match(line, endpos)
    	    if m:
                tok = str(m.group(p))
                endpos = m.end(p)
                yield tok
                break
        else:
            raise Exception('Unmatched string after %s on line %d' % (line[:endpos], lineno))

def replace_params(lineno, nextline, parameters):
    params_dict = dict([(newparam, j) for j,newparam in enumerate(parameters)])
    return ''.join([replace_name_token(t, params_dict) for t in tokens_of(lineno, nextline)])

def prescad(prefile):
    splitpoint = prefile.index('!PRESCAD!')
    r = [prefile[:splitpoint]]
    all_lines = prefile[splitpoint + 9:].split('\n')
    all_lines = [x for x in all_lines if x.lstrip()[:2] not in ('', '//')]
    pos = -2
    while pos + len(all_lines) >= 0:
        x = all_lines[pos]
        x = x[:x.index('=')].strip()
        for line in all_lines[pos+1:-1]:
            if x in line[line.index('=')+1:].strip():
                break
        else:
            if x not in all_lines[-1]:
                print("WARNING: unused parameter '" + x + "'")
                del all_lines[pos]
                continue
        pos -= 1
    func_num = 0
    parameters = []
    right_lines = []
    for x in all_lines[:-1]:
        parameters.append(x[:x.index('=')].strip())
        right_lines.append(x[x.index('=')+1:].strip())
    right_lines.append(all_lines[-1].strip())
    parameters_take = [[] for i in range(len(right_lines))]
    i = 0
    while i < len(parameters):
        p = parameters[i]
        last = None
        for j in range(i+1, len(right_lines)):
            if j != i+1 and parameters[j-1] == p:
                break
            if p in right_lines[j]:
                last = j
        if last is None:
            print("WARNING: parameter redefined before use: '" + parameters[i] + "'")
            del parameters[i]
            del right_lines[i]
            del parameters_take[i]
            continue
        for k in range(i+1, last+1):
            parameters_take[k].append(p)
        i += 1
    for i in range(len(right_lines) - 1):
        strings = ';'.join(['children(' + str(parameters_take[i].index(x)) + ')' for x in parameters_take[i+1][:-1]])
        if strings != '':
            strings += ';'

        nextline = replace_params(i+1, right_lines[i], parameters_take[i])

        r.append('module prescadfunc' + str(i) + '() prescadfunc' + str(i+1) + '() {' + strings + nextline + '}')

    nextline = replace_params(len(right_lines), right_lines[-1], parameters_take[-1])

    r.append('module prescadfunc' + str(len(right_lines) - 1) + '() ' + nextline)
    r.append('prescadfunc0();')
    r.append('')
    return '\n'.join(r)

from sys import argv

if __name__ == '__main__':
    assert argv[1][-8:] == '.prescad'
    h = open(argv[1], 'r')
    f1 = h.read()
    h.close()
    f2 = prescad(f1)
    h2 = open(argv[1][:-8] + '.scad', 'w')
    h2.write(f2)
    h2.close()