Skip to main content

context sensitive grammar parser generator for CPython

Project description

RBNF: Parser Generator for Context Sensitive Grammars

Build Status PyPI version MIT License

Tutorials

See Jupyter Notebook.

Preview

  • rbnf.zero: solution to processing complex texts. Similar to re.

    See source file Poly.rbnf.

    # parse polynomials from text.
    import rbnf.zero as ze
    ze_exp = ze.compile("import poly.[*]", use='Poly')
    print(ze_exp.match("2x^2 + 3 + 4 - 7 x^5 + 4 x + 5 x ^2 - x + 7 x ^ 11").result)
    

    Then we got output [(0, 7), (1, 3), (2, 7), (5, -7), (11, 7)].

  • CLI tool chains:

    λ rbnf.exe --help
    Available commands:
     cc
         rbnf source code compiler.
    
     - filename(positional or keyword arg)        : input source file
     - output(positional or keyword arg) = None   : output file name. default to be ...
     - name(positional or keyword arg) = 'unname' : name of language
    
     run
         You can apply immediate tests on your parser.
         P.S: use `--opt` option takes longer starting time.
    
     - filename(positional or keyword arg)    : python file generated by `rbnf` command, or rbnf sour file
     - opt(positional or keyword arg) = False : optimize switch
    
    
    
    λ printf "ignore [space]\nspace := R'\s+'\nterm := R'[^\s\(\)]+'\nsexpr ::= '(' sexpr* ')' | term" > lisp.rbnf
    λ rbnf run lisp
    
    type `:i` to switch between python mode and parsing mode.
    The last result of parsing is stored as symbol `res`.
    
    runbnf> (add 1 (add 2))
    
    sexpr[
          Tokenizer(name='auto_const', value='(', lineno=0, colno=0)
          sexpr[
                Tokenizer(name='term', value='add', lineno=0, colno=1)
          ]
          sexpr[
                Tokenizer(name='term', value='1', lineno=0, colno=5)
          ]
          sexpr[
                 Tokenizer(name='auto_const', value='(', lineno=0, colno=7)
                 sexpr[
                       Tokenizer(name='term', value='add', lineno=0, colno=8)
                 ]
                 sexpr[
                       Tokenizer(name='term', value='2', lineno=0, colno=12)
                 ]
                 Tokenizer(name='auto_const', value=')', lineno=0, colno=13)
          ]
          Tokenizer(name='auto_const', value=')', lineno=0, colno=14)
    ]
    
    runbnf> exit
    
    λ rbnf cc lisp.bnf -output lisp.py
    ...
    

Related

  • RBNF could help to develop type checker:

    https://github.com/thautwarm/reFining

    python cli.py
    
    reF> let x: 'a = 1 in
          fn x: 'a -> x ;;
    =>  (int`2 => int`2)
    
  • RBNF could help to develop programming languages:

    https://github.com/thautwarm/rmalt

    python test.py
    
    malt> let (%+) = (l, r) -> (l + r) % r;;
    malt> let f = (a, b) -> a  + b;;
    malt> f 1 2;;
    =>  3
    malt> f 1
          ;;
    =>  Fn(b)<id=3061211909288>
    malt> infix %+ 5;;
    =>  5
    malt> let (%+) = (l, r) -> (l % r) + r;;
    malt> 5 %+ 6;;
    =>  11
    
    

EDSL in Python

To be continue.

RBNF's compiler(rbnf -> python or others) relies on bootstrap.

Actually, in current version, bootstrap of RBNF is implemented in EDSL.

See rbnf bootstrap in Python.

A snippet could be previewed here.

rbnf = Language("RBNF")

...

@rbnf
class Primitive(Parser):

    @classmethod
    def bnf(cls):
        # @formatter:off
        return optimize(
                 C('(') + Or @ "or_" + C(')')
               | C('[') + Or @ "optional" + C(']')
               | Name @ "name"
               | Str  @ "str")
        # @formatter:on

     @classmethod
    def rewrite(cls, state: State):
        get = state.ctx.get
        or_: Parser = get('or_')
        optional: Parser = get('optional')
        ...

...

Other backend

To be continue.

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Files for rbnf, version 0.3.21
Filename, size File type Python version Upload date Hashes
Filename, size rbnf-0.3.21-py3-none-any.whl (44.8 kB) File type Wheel Python version py3 Upload date Hashes View hashes

Supported by

Elastic Elastic Search Pingdom Pingdom Monitoring Google Google BigQuery Sentry Sentry Error logging AWS AWS Cloud computing DataDog DataDog Monitoring Fastly Fastly CDN DigiCert DigiCert EV certificate StatusPage StatusPage Status page