Source code for pytezos.michelson.grammar

# Inspired by
from ply.lex import Lexer, lex, LexToken
from ply.yacc import yacc
import re
import json

from pytezos.michelson.macros import expand_macro

[docs]class MichelsonParserError(ValueError): def __init__(self, token: LexToken, message=None): message = message or f'failed to parse expression {token}' super(MichelsonParserError, self).__init__(message) self.message = message self.line = token.lineno self.pos = token.lexpos
[docs]class Sequence(list): pass
[docs]class SimpleMichelsonLexer(Lexer): tokens = ('INT', 'BYTE', 'STR', 'ANNOT', 'PRIM', 'LEFT_CURLY', 'RIGHT_CURLY', 'LEFT_PAREN', 'RIGHT_PAREN', 'SEMI') t_INT = r'-?[0-9]+' t_BYTE = r'0x[A-Fa-f0-9]*' t_STR = r'\"(\\.|[^\"])*\"' t_ANNOT = r'[:@%]+([_0-9a-zA-Z\.]*)?' # r'[:@%]+([_a-zA-Z][_0-9a-zA-Z\.]*)?' t_PRIM = r'[A-Za-z][A-Za-z0-9_]+' t_LEFT_CURLY = r'\{' t_RIGHT_CURLY = r'\}' t_LEFT_PAREN = r'\(' t_RIGHT_PAREN = r'\)' t_SEMI = r';' t_ignore_MULTI_COMMENT = r'/\*.*?\*/' t_ignore_COMMENT = r'#[^\n]*' t_ignore = ' \t\r\n\f' def __init__(self): super(SimpleMichelsonLexer, self).__init__() self.lexer = lex(module=self, reflags=re.MULTILINE)
[docs] def t_error(self, t): t.type = t.value[0] t.value = t.value[0] t.lexer.skip(1) return t
[docs]class MichelsonParser(object): """ Customizable Michelson parser """ tokens = SimpleMichelsonLexer.tokens
[docs] def p_instr(self, p): '''instr : expr | empty ''' p[0] = p[1]
[docs] def p_instr_int(self, p): '''instr : INT''' p[0] = {'int': p[1]}
[docs] def p_instr_byte(self, p): '''instr : BYTE''' p[0] = {'bytes': p[1][2:]} # strip 0x prefix
[docs] def p_instr_str(self, p): '''instr : STR''' p[0] = {'string': json.loads(p[1])}
[docs] def p_instr_list(self, p): '''instr : instr SEMI instr''' p[0] = list() for i in [p[1], p[3]]: if type(i) is list: p[0].extend(i) elif i is not None: p[0].append(i)
[docs] def p_instr_subseq(self, p): '''instr : LEFT_CURLY instr RIGHT_CURLY''' p[0] = Sequence() if type(p[2]) is list: p[0].extend(p[2]) elif p[2] is not None: p[0].append(p[2])
[docs] def p_expr(self, p): '''expr : PRIM annots args''' try: expr = expand_macro( prim=p[1], annots=p[2] or [], args=p[3] or [], extra=self.extra ) except AssertionError as e: raise MichelsonParserError(p.slice[1], str(e)) p[0] = Sequence(expr) if isinstance(expr, list) else expr
[docs] def p_annots(self, p): '''annots : annot | empty ''' if p[1] is not None: p[0] = [p[1]]
[docs] def p_annots_list(self, p): '''annots : annots annot''' p[0] = list() if type(p[1]) == list: p[0].extend(p[1]) if p[2] is not None: p[0].append(p[2])
[docs] def p_annot(self, p): '''annot : ANNOT''' p[0] = p[1]
[docs] def p_args(self, p): '''args : arg | empty ''' p[0] = list() if p[1] is not None: p[0].append(p[1])
[docs] def p_args_list(self, p): '''args : args arg''' p[0] = list() if type(p[1]) == list: p[0].extend(p[1]) if p[2] is not None: p[0].append(p[2])
[docs] def p_arg_prim(self, p): '''arg : PRIM''' p[0] = {'prim': p[1]}
[docs] def p_arg_int(self, p): '''arg : INT''' p[0] = {'int': p[1]}
[docs] def p_arg_byte(self, p): '''arg : BYTE''' p[0] = {'bytes': p[1][2:]} # strip 0x prefix
[docs] def p_arg_str(self, p): '''arg : STR''' p[0] = {'string': json.loads(p[1])}
[docs] def p_arg_subseq(self, p): '''arg : LEFT_CURLY instr RIGHT_CURLY''' if type(p[2]) == list: p[0] = p[2] elif p[2] is not None: p[0] = [p[2]] else: p[0] = []
[docs] def p_arg_group(self, p): '''arg : LEFT_PAREN expr RIGHT_PAREN''' p[0] = p[2]
[docs] def p_empty(self, p): '''empty :'''
[docs] def p_error(self, p): raise MichelsonParserError(p)
def __init__(self, debug=False, write_tables=False, extra_primitives=None): """ Initialize Michelson parser :param debug: Verbose output :param write_tables: Store PLY output :param extra_primitives: List of words to be ignored """ self.lexer = SimpleMichelsonLexer() self.parser = yacc( module=self, debug=debug, write_tables=write_tables, ) self.extra = extra_primitives
[docs] def parse(self, code): """ Parse Michelson source. :param code: Michelson source :returns: Micheline expression """ if len(code) > 0 and code[0] == '(' and code[-1] == ')': code = code[1:-1] return self.parser.parse(code)