def make_mgr_parser(input_file, initial_states, output_file):
"""Creates a parser from a .mgr grammar file."""
print("=====", input_file, "->", output_file, "=====")
grammar = mgr.read.read_grammar(input_file, initial_states)
type = grammar.properties.get('type')
if type == 'LL':
output = makell.make_ll_parser(grammar)
elif type == 'LR':
output = makelr.make_lr_parser(grammar)
elif type:
raise Exception('File %r specifies unknown "type"' % input_file)
else:
raise Exception('File %r does not specify "type"' % input_file)
with open(output_file, 'w') as f:
f.write(output)
def make_mgr_parser(input_file, initial_states, output_file):
"""Creates a parser from a .mgr grammar file."""
print("=====", input_file, "->", output_file, "=====")
grammar = mgr.read.read_grammar(input_file, initial_states)
type = grammar.properties.get('type')
if type == 'LL':
output = makell.make_ll_parser(grammar)
elif type == 'LR':
output = makelr.make_lr_parser(grammar)
elif type:
raise Exception('File %r specifies unknown "type"' % input_file)
else:
raise Exception('File %r does not specify "type"' % input_file)
with open(output_file, 'w') as f:
f.write(output)
# stat -> HELLO | IF cond THEN stat | IF cond THEN stat ELSE stat
"stat": [(("HELLO",), "lambda ctx, a: 'hello'"),
(("IF", "cond", "THEN", "stat"),
"lambda ctx, a, b, c, d: ('if', b, d, None)"),
(("IF", "cond", "THEN", "stat", "ELSE", "stat"),
"lambda ctx, a, b, c, d, e, f: ('if', b, d, f)")],
# cond -> cond AND cond | cond OR cond | TRUE | FALSE
"cond": [(("cond", "AND", "cond"), "lambda ctx, a, b, c: (a, 'and', c)"),
(("cond", "OR", "cond"), "lambda ctx, a, b, c: (a, 'or', c)"),
(("TRUE",), "lambda ctx, a: True"),
(("FALSE",), "lambda ctx, a: False")],
}
properties = {
"default_start": "stat",
"precedence": [
[
("left", ["OR"]),
("left", ["AND"]),
],
[
("precedence", [("stat", ("IF", "cond", "THEN", "stat"))]),
("precedence", ["ELSE"]),
],
],
}
my_grammar = Grammar(preface, properties, rules)
print(make_lr_parser(my_grammar))
"stat": [(("HELLO", ), "lambda ctx, a: 'hello'"),
(("IF", "cond", "THEN", "stat"),
"lambda ctx, a, b, c, d: ('if', b, d, None)"),
(("IF", "cond", "THEN", "stat", "ELSE", "stat"),
"lambda ctx, a, b, c, d, e, f: ('if', b, d, f)")],
# cond -> cond AND cond | cond OR cond | TRUE | FALSE
"cond": [(("cond", "AND", "cond"), "lambda ctx, a, b, c: (a, 'and', c)"),
(("cond", "OR", "cond"), "lambda ctx, a, b, c: (a, 'or', c)"),
(("TRUE", ), "lambda ctx, a: True"),
(("FALSE", ), "lambda ctx, a: False")],
}
properties = {
"default_start":
"stat",
"precedence": [
[
("left", ["OR"]),
("left", ["AND"]),
],
[
("precedence", [("stat", ("IF", "cond", "THEN", "stat"))]),
("precedence", ["ELSE"]),
],
],
}
my_grammar = Grammar(preface, properties, rules)
print(make_lr_parser(my_grammar))