dfmparse.py

"""
This module can parse a Delphi Form (dfm) file.

The main is used in experimenting (to find which files fail
to parse, and where), but isn't useful for anything else.
"""
__version__ = "1.0"
__author__ = "Daniel 'Dang' Griffith <pythondev - dang at lazytwinacres . net>"


from pyparsing import (
    Literal,
    CaselessLiteral,
    Word,
    delimitedList,
    Optional,
    Combine,
    Group,
    alphas,
    nums,
    alphanums,
    Forward,
    oneOf,
    OneOrMore,
    ZeroOrMore,
    CharsNotIn,
)


# This converts DFM character constants into Python string (unicode) values.
def to_chr(x):
    """chr(x) if 0 < x < 128 ; unicode(x) if x > 127."""
    return 0 < x < 128 and chr(x) or eval("u'\\u%d'" % x)


#################
# BEGIN GRAMMAR
#################

COLON = Literal(":").suppress()
CONCAT = Literal("+").suppress()
EQUALS = Literal("=").suppress()
LANGLE = Literal("<").suppress()
LBRACE = Literal("[").suppress()
LPAREN = Literal("(").suppress()
PERIOD = Literal(".").suppress()
RANGLE = Literal(">").suppress()
RBRACE = Literal("]").suppress()
RPAREN = Literal(")").suppress()

CATEGORIES = CaselessLiteral("categories").suppress()
END = CaselessLiteral("end").suppress()
FONT = CaselessLiteral("font").suppress()
HINT = CaselessLiteral("hint").suppress()
ITEM = CaselessLiteral("item").suppress()
OBJECT = CaselessLiteral("object").suppress()

attribute_value_pair = Forward()  # this is recursed in item_list_entry

simple_identifier = Word(alphas, alphanums + "_")
identifier = Combine(simple_identifier + ZeroOrMore(Literal(".") + simple_identifier))
object_name = identifier
object_type = identifier

# Integer and floating point values are converted to Python longs and floats, respectively.
int_value = Combine(Optional("-") + Word(nums)).setParseAction(
    lambda s, l, t: [int(t[0])]
)
float_value = Combine(
    Optional("-") + Optional(Word(nums)) + "." + Word(nums)
).setParseAction(lambda s, l, t: [float(t[0])])
number_value = float_value | int_value

# Base16 constants are left in string form, including the surrounding braces.
base16_value = Combine(
    Literal("{") + OneOrMore(Word("0123456789ABCDEFabcdef")) + Literal("}"),
    adjacent=False,
)

# This is the first part of a hack to convert the various delphi partial sglQuotedStrings
#     into a single sglQuotedString equivalent.  The gist of it is to combine
#     all sglQuotedStrings (with their surrounding quotes removed (suppressed))
#     with sequences of #xyz character constants, with "strings" concatenated
#     with a '+' sign.
unquoted_sglQuotedString = Combine(
    Literal("'").suppress() + ZeroOrMore(CharsNotIn("'\n\r")) + Literal("'").suppress()
)

# The parse action on this production converts repetitions of constants into a single string.
pound_char = Combine(
    OneOrMore(
        (Literal("#").suppress() + Word(nums)).setParseAction(
            lambda s, l, t: to_chr(int(t[0]))
        )
    )
)

# This is the second part of the hack.  It combines the various "unquoted"
#     partial strings into a single one.  Then, the parse action puts
#     a single matched pair of quotes around it.
delphi_string = Combine(
    OneOrMore(CONCAT | pound_char | unquoted_sglQuotedString), adjacent=False
).setParseAction(lambda s, l, t: f"'{t[0]}'")

string_value = delphi_string | base16_value

list_value = (
    LBRACE
    + Optional(Group(delimitedList(identifier | number_value | string_value)))
    + RBRACE
)
paren_list_value = (
    LPAREN + ZeroOrMore(identifier | number_value | string_value) + RPAREN
)

item_list_entry = ITEM + ZeroOrMore(attribute_value_pair) + END
item_list = LANGLE + ZeroOrMore(item_list_entry) + RANGLE

generic_value = identifier
value = (
    item_list
    | number_value
    | string_value
    | list_value
    | paren_list_value
    | generic_value
)

category_attribute = CATEGORIES + PERIOD + oneOf("strings itemsvisibles visibles", True)
event_attribute = oneOf(
    "onactivate onclosequery onclose oncreate ondeactivate onhide onshow", True
)
font_attribute = FONT + PERIOD + oneOf("charset color height name style", True)
hint_attribute = HINT
layout_attribute = oneOf("left top width height", True)
generic_attribute = identifier
attribute = (
    category_attribute
    | event_attribute
    | font_attribute
    | hint_attribute
    | layout_attribute
    | generic_attribute
)

category_attribute_value_pair = category_attribute + EQUALS + paren_list_value
event_attribute_value_pair = event_attribute + EQUALS + value
font_attribute_value_pair = font_attribute + EQUALS + value
hint_attribute_value_pair = hint_attribute + EQUALS + value
layout_attribute_value_pair = layout_attribute + EQUALS + value
generic_attribute_value_pair = attribute + EQUALS + value
attribute_value_pair << Group(
    category_attribute_value_pair
    | event_attribute_value_pair
    | font_attribute_value_pair
    | hint_attribute_value_pair
    | layout_attribute_value_pair
    | generic_attribute_value_pair
)

object_declaration = Group(OBJECT + object_name + COLON + object_type)
object_attributes = Group(ZeroOrMore(attribute_value_pair))

nested_object = Forward()
object_definition = (
    object_declaration + object_attributes + ZeroOrMore(nested_object) + END
)
nested_object << Group(object_definition)

#################
# END GRAMMAR
#################


def printer(s, loc, tok):
    print(tok, end=" ")
    return tok


def get_filename_list(tf):
    import sys, glob

    if tf == None:
        if len(sys.argv) > 1:
            tf = sys.argv[1:]
        else:
            tf = glob.glob("*.dfm")
    elif type(tf) == str:
        tf = [tf]
    testfiles = []
    for arg in tf:
        testfiles.extend(glob.glob(arg))
    return testfiles


def main(testfiles=None, action=printer):
    """testfiles can be None, in which case the command line arguments are used as filenames.
    testfiles can be a string, in which case that file is parsed.
    testfiles can be a list.
    In all cases, the filenames will be globbed.
    If more than one file is parsed successfully, a dictionary of ParseResults is returned.
    Otherwise, a simple ParseResults is returned.
    """
    testfiles = get_filename_list(testfiles)
    print(testfiles)

    if action:
        for i in (simple_identifier, value, item_list):
            i.setParseAction(action)

    success = 0
    failures = []

    retval = {}
    for f in testfiles:
        try:
            retval[f] = object_definition.parseFile(f)
            success += 1
        except Exception:
            failures.append(f)

    nl = "\n"
    if failures:
        print(f"{nl}failed while processing {', '.join(failures)}")
    print(f"{nl}succeeded on {success} of {len(testfiles)} files")

    if len(retval) == 1 and len(testfiles) == 1:
        # if only one file is parsed, return the parseResults directly
        return retval[list(retval.keys())[0]]

    # else, return a dictionary of parseResults
    return retval


if __name__ == "__main__":
    main()