Introduction
Abstract
Extension of pyparsing. You can easily build your own languages. ✌️
Keywords
- PEG
- Regular Expressions
- Parser
- Formal Grammar
Awesome Feature:
1. mixedExpression
2. build languages (see example)
Requirements
pyparsing
Download
pip install pyparsing_ext
Structure
- core: basic token classes
- actions: classes for parsing actions
- expressions: complicated expressions
- utils: some useful tools
Content
Classes::
Tokens:
Wordx: powerful Word
CharsNot: powerful CharsNotIn
PrecededBy: as FollowedBy
MeanWhile:
LinenStart:
Actions:
BaseAction: Base Class of Actions
BifixAction: action for bifix operators such as <x,y>
...
Functions::
keyRange(s)
ordRange(s)
chrRange(s)
CJK # for matching Chinese Japanese Korean
enumeratedItems
delimitedMatrix # delimitedList with two sepsExample
w = Wordx(lambda x: x in {'a', 'b', 'c', 'd'}) # == Word('abcd')
M = delimitedMatrix(w, ch1=' ', ch2=pp.Regex('\n+').leaveWhitespace())
p = M.parseString('a b\n c d')
print(p.asList())
s = '''
[1]hello, world
[2]hello, kitty
'''
print(enumeratedItems().parseString(s))
cjk = ordRange(0x4E00, 0x9FD5)
cjk.parseString('我爱你, I love you') # => ['我爱你']
cjk = ordRanges((0x4E00, 0x9FD5, 0, 256))
cjk.parseString('我爱你 I love you') # => ['我爱你 I love you']
import pyparsing as pp
integer = pp.pyparsing_common.signed_integer
varname = pp.pyparsing_common.identifier
arithOplist = [('-', 1, pp.opAssoc.RIGHT),
(pp.oneOf('* /'), 2, pp.opAssoc.LEFT),
(pp.oneOf('+ -'), 2, pp.opAssoc.LEFT)]
def func(EXP):
return pp.Group('<' + EXP + pp.Suppress(',') + EXP +'>')| pp.Group('||' + EXP + '||') | pp.Group('|' + EXP + '|') | pp.Group(IDEN + '(' + pp.delimitedList(EXP) + ')')
baseExpr = integer | varname
EXP = mixedExpression(baseExpr, func=func, opList=arithOplist)
a = EXP.parseString('5*g(|-3|)+<4,5> + f(6)')
print(a)
# [[[5, '*', ['g', '(', ['|', ['-', 3], '|'], ')']], '+', ['<', 4, 5, '>'], '+', ['f', '(', 6, ')']]]build your own languages
import pyparsing_ext.pylang
pyparsing_ext.pylang.example
pyparsing_ext.pylang.example.smallpy.cmdline() # in mode of command lineoutput:
Example 1:
|-1| -> ('|', '|')(-(1))
Example 2:
parse source code:
x=|-1|; # absolute value
y=x*2+1;
if x == 1
{z=[3.3_]; # the floor value
}
print "z =", z;
result:
z = 3
see the dictionary of variables:
{'x': Decimal('1'), 'y': Decimal('3'), 'z': 3}
React
Typescript
Django
Laravel
Facebook
Microsoft
Google
Alibaba
D3
Tencent