| Server IP : 109.234.164.53 / Your IP : 216.73.216.110 Web Server : Apache System : Linux cervelle.o2switch.net 4.18.0-553.32.1.lve.el8.x86_64 #1 SMP Thu Dec 19 13:14:03 UTC 2024 x86_64 User : computer3 ( 1098) PHP Version : 7.1.33 Disable Function : NONE MySQL : OFF | cURL : ON | WGET : ON | Perl : ON | Python : ON | Sudo : OFF | Pkexec : OFF Directory : /proc/845366/root/opt/alt/python37/share/doc/alt-python37-pyparsing-doc/examples/ |
Upload File : |
#
# lua_parser.py
#
# A simple parser for the Lua language.
#
# Copyright 2020, Paul McGuire
#
"""
from https://www.lua.org/manual/5.1/manual.html#8
chunk ::= {stat [';']} [laststat [';']]
block ::= chunk
stat ::= varlist '=' explist |
functioncall |
do block end |
while exp do block end |
repeat block until exp |
if exp then block {elseif exp then block} [else block] end |
for Name '=' exp ',' exp [',' exp] do block end |
for namelist in explist do block end |
function funcname funcbody |
local function Name funcbody |
local namelist ['=' explist]
laststat ::= return [explist] | break
funcname ::= Name {'.' Name} [':' Name]
varlist ::= var {',' var}
var ::= Name | prefixexp '[' exp ']' | prefixexp '.' Name
namelist ::= Name {',' Name}
explist ::= {exp ','} exp
exp ::= nil | false | true | Number | String | '...' | function |
prefixexp | tableconstructor | exp binop exp | unop exp
prefixexp ::= var | functioncall | '(' exp ')'
functioncall ::= prefixexp args | prefixexp ':' Name args
args ::= '(' [explist] ')' | tableconstructor | String
function ::= function funcbody
funcbody ::= '(' [parlist] ')' block end
parlist ::= namelist [',' '...'] | '...'
tableconstructor ::= '{' [fieldlist] '}'
fieldlist ::= field {fieldsep field} [fieldsep]
field ::= '[' exp ']' '=' exp | Name '=' exp | exp
fieldsep ::= ',' | ';'
binop ::= '+' | '-' | '*' | '/' | '^' | '%' | '..' |
'<' | '<=' | '>' | '>=' | '==' | '~=' |
and | or
unop ::= '-' | not | '#'
operator precedence:
or
and
< > <= >= ~= ==
|
~
&
<< >>
..
+ -
* / // %
unary operators (not # - ~)
^
"""
import pyparsing as pp
ppc = pp.pyparsing_common
pp.ParserElement.enablePackrat()
LBRACK, RBRACK, LBRACE, RBRACE, LPAR, RPAR, EQ, COMMA, SEMI, COLON = map(
pp.Suppress, "[]{}()=,;:"
)
OPT_SEMI = pp.Optional(SEMI).suppress()
ELLIPSIS = pp.Literal("...")
keywords = {
k.upper(): pp.Keyword(k)
for k in """\
return break do end while if then elseif else for in function local repeat until nil false true and or not
""".split()
}
vars().update(keywords)
any_keyword = pp.MatchFirst(keywords.values()).setName("<keyword>")
comment_intro = pp.Literal("--")
short_comment = comment_intro + pp.restOfLine
long_comment = comment_intro + LBRACK + ... + RBRACK
lua_comment = long_comment | short_comment
# must use negative lookahead to ensure we don't parse a keyword as an identifier
ident = ~any_keyword + ppc.identifier
name = pp.delimitedList(ident, delim=".", combine=True)
namelist = pp.delimitedList(name)
number = ppc.number
# does not parse levels
multiline_string = pp.QuotedString("[[", endQuoteChar="]]", multiline=True)
string = pp.QuotedString("'") | pp.QuotedString('"') | multiline_string
exp = pp.Forward()
# explist1 ::= {exp ','} exp
explist1 = pp.delimitedList(exp)
stat = pp.Forward()
# laststat ::= return [explist1] | break
laststat = pp.Group(RETURN + explist1) | BREAK
# block ::= {stat [';']} [laststat[';']]
block = pp.Group(stat + OPT_SEMI)[1, ...] + pp.Optional(laststat + OPT_SEMI)
# field ::= '[' exp ']' '=' exp | Name '=' exp | exp
field = pp.Group(
LBRACK + exp + RBRACK + EQ + pp.Group(exp) | name + EQ + pp.Group(exp) | exp
)
# fieldsep ::= ',' | ';'
fieldsep = COMMA | SEMI
# fieldlist ::= field {fieldsep field} [fieldsep]
field_list = pp.delimitedList(field, delim=fieldsep) + pp.Optional(fieldsep)
# tableconstructor ::= '{' [fieldlist] '}'
tableconstructor = pp.Group(LBRACE + pp.Optional(field_list) + RBRACE)
# parlist1 ::= namelist [',' '...'] | '...'
parlist = namelist + pp.Optional(COMMA + ELLIPSIS) | ELLIPSIS
# funcname ::= Name {'.' Name} [':' Name]
funcname = pp.Group(name + COLON + name) | name
# function ::= function funcbody
# funcbody ::= '(' [parlist1] ')' block end
funcbody = pp.Group(LPAR + parlist + RPAR) + block + END
function = FUNCTION + funcbody
# args ::= '(' [explist1] ')' | tableconstructor | String
args = LPAR + pp.Optional(explist1) + RPAR | tableconstructor | string
# this portion of the spec is left-recursive, must break LR loop
# varlist1 ::= var {',' var}
# var ::= Name | prefixexp '[' exp ']' | prefixexp '.' Name
# prefixexp ::= var | functioncall | '(' exp ')'
# functioncall ::= prefixexp args | prefixexp ':' Name args
prefixexp = name | LPAR + exp + RPAR
functioncall = prefixexp + args | prefixexp + COLON + name + args
var = pp.Forward()
var_atom = functioncall | name | LPAR + exp + RPAR
index_ref = pp.Group(LBRACK + exp + RBRACK)
var <<= pp.delimitedList(pp.Group(var_atom + index_ref) | var_atom, delim=".")
varlist1 = pp.delimitedList(var)
# exp ::= nil | false | true | Number | String | '...' |
# function | prefixexp | tableconstructor
exp_atom = (
NIL
| FALSE
| TRUE
| number
| string
| ELLIPSIS
| functioncall
| var # prefixexp
| tableconstructor
)
# precedence of operations from https://www.lua.org/manual/5.3/manual.html#3.4.8
exp <<= pp.infixNotation(
exp_atom,
[
("^", 2, pp.opAssoc.LEFT),
(NOT | pp.oneOf("# - ~"), 1, pp.opAssoc.RIGHT),
(pp.oneOf("* / // %"), 2, pp.opAssoc.LEFT),
(pp.oneOf("+ -"), 2, pp.opAssoc.LEFT),
("..", 2, pp.opAssoc.LEFT),
(pp.oneOf("<< >>"), 2, pp.opAssoc.LEFT),
("&", 2, pp.opAssoc.LEFT),
("~", 2, pp.opAssoc.LEFT),
("|", 2, pp.opAssoc.LEFT),
(pp.oneOf("< > <= >= ~= =="), 2, pp.opAssoc.LEFT),
(AND, 2, pp.opAssoc.LEFT),
(OR, 2, pp.opAssoc.LEFT),
],
)
assignment_stat = pp.Optional(LOCAL) + varlist1 + EQ + explist1
func_call_stat = pp.Optional(LOCAL) + functioncall
do_stat = DO + block + END
while_stat = WHILE + exp + block + END
repeat_stat = REPEAT + block + UNTIL + exp
for_loop_stat = (
FOR + name + EQ + exp + COMMA + exp + pp.Optional(COMMA + exp) + DO + block + END
)
for_seq_stat = FOR + namelist + IN + explist1 + DO + block + END
if_stat = (
IF
+ exp
+ THEN
+ block
+ pp.Group(ELSEIF + exp + THEN + block)[...]
+ pp.Optional(pp.Group(ELSE + block))
+ END
)
function_def = pp.Optional(LOCAL) + FUNCTION + funcname + funcbody
for var_name in """
assignment_stat
func_call_stat
do_stat
while_stat
repeat_stat
for_loop_stat
for_seq_stat
if_stat
function_def
""".split():
vars()[var_name].setName(var_name)
# stat ::= varlist1 '=' explist1 |
# functioncall |
# do block end |
# while exp do block end |
# repeat block until exp |
# if exp then block {elseif exp then block} [else block] end |
# for Name '=' exp ',' exp [',' exp] do block end |
# for namelist in explist1 do block end |
# function funcname funcbody |
# local function Name funcbody |
# local namelist ['=' explist1]
stat <<= pp.Group(
assignment_stat
| do_stat
| while_stat
| repeat_stat
| for_loop_stat
| for_seq_stat
| func_call_stat
| if_stat
| function_def
)
lua_script = stat[...]
# ignore comments
lua_script.ignore(lua_comment)
if __name__ == "__main__":
sample = r"""
function test(x)
local t = {foo=1, bar=2, arg=x}
n = 0
if t['foo'] then
n = n + 1
end
if 10 > 8 then
n = n + 2
end
if (10 > 8) then
n = n + 2
end
end
"""
try:
result = lua_script.parseString(sample)
result.pprint()
except pp.ParseException as pe:
print(pe.explain())