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David Beazley 2017-02-01 13:15:34 -06:00
parent d614aa0e04
commit b6357d2491
4 changed files with 51 additions and 53 deletions
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4
README.md
View File

@ -1,6 +1,6 @@
SLY (Sly Lex-Yacc) Version 0.0
Copyright (C) 2016
Copyright (C) 2016-2017
David M. Beazley (Dabeaz LLC)
All rights reserved.
@ -37,7 +37,7 @@ USE AT YOUR OWN RISK.
Requirements
============
SLY requires the use of Python 3.5 or greater. Older versions
SLY requires the use of Python 3.6 or greater. Older versions
of Python are not supported.
Introduction

2
example/calc/calc.py
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@ -64,7 +64,7 @@ class CalcParser(Parser):
def expr(self, p):
return p.term
@_('term TIMES factor1')
@_('term TIMES factor')
def term(self, p):
return p.term * p.factor

18
sly/lex.py
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@ -66,7 +66,7 @@ class Token(object):
'''
__slots__ = ('type', 'value', 'lineno', 'index')
def __repr__(self):
return 'Token(type=%r, value=%r, lineno=%d, index=%d)' % (self.type, self.value, self.lineno, self.index)
return f'Token(type={self.type!r}, value={self.value!r}, lineno={self.lineno}, index={self.index}'
class LexerMetaDict(OrderedDict):
'''
@ -78,7 +78,7 @@ class LexerMetaDict(OrderedDict):
if callable(value):
value.pattern = self[key]
else:
raise AttributeError('Name %s redefined' % (key))
raise AttributeError(f'Name {key} redefined')
super().__setitem__(key, value)
@ -92,7 +92,7 @@ class LexerMeta(type):
def _(pattern, *extra):
patterns = [pattern, *extra]
def decorate(func):
pattern = '|'.join('(%s)' % pat for pat in patterns )
pattern = '|'.join(f'({pat})' for pat in patterns )
if hasattr(func, 'pattern'):
func.pattern = pattern + '|' + func.pattern
else:
@ -140,7 +140,7 @@ class Lexer(metaclass=LexerMeta):
Validate the rules to make sure they look sane.
'''
if 'tokens' not in vars(cls):
raise LexerBuildError('%s class does not define a tokens attribute' % cls.__qualname__)
raise LexerBuildError(f'{cls.__qualname__} class does not define a tokens attribute')
cls._token_names = cls._token_names | set(cls.tokens)
cls._literals = cls._literals | set(cls.literals)
@ -161,17 +161,17 @@ class Lexer(metaclass=LexerMeta):
cls._token_funcs[tokname] = value
# Form the regular expression component
part = '(?P<%s>%s)' % (tokname, pattern)
part = f'(?P<{tokname}>{pattern})'
# Make sure the individual regex compiles properly
try:
cpat = re.compile(part, cls.reflags)
except Exception as e:
raise PatternError('Invalid regex for token %s' % tokname) from e
raise PatternError(f'Invalid regex for token {tokname}') from e
# Verify that the pattern doesn't match the empty string
if cpat.match(''):
raise PatternError('Regex for token %s matches empty input' % tokname)
raise PatternError(f'Regex for token {tokname} matches empty input')
parts.append(part)
@ -187,7 +187,7 @@ class Lexer(metaclass=LexerMeta):
raise LexerBuildError('ignore specifier must be a string')
if not all(isinstance(lit, str) for lit in cls.literals):
raise LexerBuildError("literals must be specified as strings")
raise LexerBuildError('literals must be specified as strings')
def tokenize(self, text, lineno=1, index=0):
# Local copies of frequently used values
@ -252,4 +252,4 @@ class Lexer(metaclass=LexerMeta):
# Default implementations of the error handler. May be changed in subclasses
def error(self, value):
raise LexError("Illegal character %r at index %d" % (value[0], self.index), value)
raise LexError(f'Illegal character {value[0]!r} at index {self.index}', value)

80
sly/yacc.py
View File

@ -1,7 +1,7 @@
# -----------------------------------------------------------------------------
# sly: yacc.py
#
# Copyright (C) 2016
# Copyright (C) 2016-2017
# David M. Beazley (Dabeaz LLC)
# All rights reserved.
#
@ -224,7 +224,7 @@ class Production(object):
if self.prod:
s = '%s -> %s' % (self.name, ' '.join(self.prod))
else:
s = '%s -> <empty>' % self.name
s = f'{self.name} -> <empty>'
if self.prec[1]:
s += ' [precedence=%s, level=%d]' % self.prec
@ -232,7 +232,7 @@ class Production(object):
return s
def __repr__(self):
return 'Production(' + str(self) + ')'
return f'Production({self})'
def __len__(self):
return len(self.prod)
@ -300,11 +300,11 @@ class LRItem(object):
if self.prod:
s = '%s -> %s' % (self.name, ' '.join(self.prod))
else:
s = '%s -> <empty>' % self.name
s = f'{self.name} -> <empty>'
return s
def __repr__(self):
return 'LRItem(' + str(self) + ')'
return f'LRItem({self})'
# -----------------------------------------------------------------------------
# rightmost_terminal()
@ -384,7 +384,7 @@ class Grammar(object):
def set_precedence(self, term, assoc, level):
assert self.Productions == [None], 'Must call set_precedence() before add_production()'
if term in self.Precedence:
raise GrammarError('Precedence already specified for terminal %r' % term)
raise GrammarError(f'Precedence already specified for terminal {term!r}')
if assoc not in ['left', 'right', 'nonassoc']:
raise GrammarError("Associativity must be one of 'left','right', or 'nonassoc'")
self.Precedence[term] = (assoc, level)
@ -409,17 +409,16 @@ class Grammar(object):
def add_production(self, prodname, syms, func=None, file='', line=0):
if prodname in self.Terminals:
raise GrammarError('%s:%d: Illegal rule name %r. Already defined as a token' % (file, line, prodname))
raise GrammarError(f'{file}:{line}: Illegal rule name {prodname!r}. Already defined as a token')
if prodname == 'error':
raise GrammarError('%s:%d: Illegal rule name %r. error is a reserved word' % (file, line, prodname))
raise GrammarError(f'{file}:{line}: Illegal rule name {prodname!r}. error is a reserved word')
# Look for literal tokens
for n, s in enumerate(syms):
if s[0] in "'\"" and s[0] == s[-1]:
c = s[1:-1]
if (len(c) != 1):
raise GrammarError('%s:%d: Literal token %s in rule %r may only be a single character' %
(file, line, s, prodname))
raise GrammarError(f'{file}:{line}: Literal token {s} in rule {prodname!r} may only be a single character')
if c not in self.Terminals:
self.Terminals[c] = []
syms[n] = c
@ -428,14 +427,13 @@ class Grammar(object):
# Determine the precedence level
if '%prec' in syms:
if syms[-1] == '%prec':
raise GrammarError('%s:%d: Syntax error. Nothing follows %%prec' % (file, line))
raise GrammarError(f'{file}:{line}: Syntax error. Nothing follows %%prec')
if syms[-2] != '%prec':
raise GrammarError('%s:%d: Syntax error. %%prec can only appear at the end of a grammar rule' %
(file, line))
raise GrammarError(f'{file}:{line}: Syntax error. %prec can only appear at the end of a grammar rule')
precname = syms[-1]
prodprec = self.Precedence.get(precname)
if not prodprec:
raise GrammarError('%s:%d: Nothing known about the precedence of %r' % (file, line, precname))
raise GrammarError(f'{file}:{line}: Nothing known about the precedence of {precname!r}')
else:
self.UsedPrecedence.add(precname)
del syms[-2:] # Drop %prec from the rule
@ -448,8 +446,8 @@ class Grammar(object):
map = '%s -> %s' % (prodname, syms)
if map in self.Prodmap:
m = self.Prodmap[map]
raise GrammarError('%s:%d: Duplicate rule %s. ' % (file, line, m) +
'Previous definition at %s:%d' % (m.file, m.line))
raise GrammarError(f'{file}:{line}: Duplicate rule {m}. ' +
f'Previous definition at {m.file}:{m.line}')
# From this point on, everything is valid. Create a new Production instance
pnumber = len(self.Productions)
@ -488,7 +486,7 @@ class Grammar(object):
start = self.Productions[1].name
if start not in self.Nonterminals:
raise GrammarError('start symbol %s undefined' % start)
raise GrammarError(f'start symbol {start} undefined')
self.Productions[0] = Production(0, "S'", [start])
self.Nonterminals[start].append(0)
self.Start = start
@ -820,13 +818,13 @@ class Grammar(object):
out = []
out.append('Grammar:\n')
for n, p in enumerate(self.Productions):
out.append('Rule %-5d %s' % (n, p))
out.append(f'Rule {n:<5d} {p}')
unused_terminals = self.unused_terminals()
if unused_terminals:
out.append('\nUnused terminals:\n')
for term in unused_terminals:
out.append(' %s' % term)
out.append(f' {term}')
out.append('\nTerminals, with rules where they appear:\n')
for term in sorted(self.Terminals):
@ -1368,9 +1366,9 @@ class LRTable(object):
st_actionp = {}
st_goto = {}
descrip.append('\nstate %d\n' % st)
descrip.append(f'\nstate {st}\n')
for p in I:
descrip.append(' (%d) %s' % (p.number, p))
descrip.append(f' ({p.number}) {p}')
for p in I:
if p.len == p.lr_index + 1:
@ -1382,7 +1380,7 @@ class LRTable(object):
# We are at the end of a production. Reduce!
laheads = p.lookaheads[st]
for a in laheads:
actlist.append((a, p, 'reduce using rule %d (%s)' % (p.number, p)))
actlist.append((a, p, f'reduce using rule {p.number} ({p})'))
r = st_action.get(a)
if r is not None:
# Have a shift/reduce or reduce/reduce conflict
@ -1402,7 +1400,7 @@ class LRTable(object):
st_action[a] = -p.number
st_actionp[a] = p
if not slevel and not rlevel:
descrip.append(' ! shift/reduce conflict for %s resolved as reduce' % a)
descrip.append(f' ! shift/reduce conflict for {a} resolved as reduce')
self.sr_conflicts.append((st, a, 'reduce'))
Productions[p.number].reduced += 1
elif (slevel == rlevel) and (rprec == 'nonassoc'):
@ -1410,7 +1408,7 @@ class LRTable(object):
else:
# Hmmm. Guess we'll keep the shift
if not rlevel:
descrip.append(' ! shift/reduce conflict for %s resolved as shift' % a)
descrip.append(f' ! shift/reduce conflict for {a} resolved as shift')
self.sr_conflicts.append((st, a, 'shift'))
elif r < 0:
# Reduce/reduce conflict. In this case, we favor the rule
@ -1429,7 +1427,7 @@ class LRTable(object):
descrip.append(' ! reduce/reduce conflict for %s resolved using rule %d (%s)' %
(a, st_actionp[a].number, st_actionp[a]))
else:
raise LALRError('Unknown conflict in state %d' % st)
raise LALRError(f'Unknown conflict in state {st}')
else:
st_action[a] = -p.number
st_actionp[a] = p
@ -1442,13 +1440,13 @@ class LRTable(object):
j = self.lr0_cidhash.get(id(g), -1)
if j >= 0:
# We are in a shift state
actlist.append((a, p, 'shift and go to state %d' % j))
actlist.append((a, p, f'shift and go to state {j}'))
r = st_action.get(a)
if r is not None:
# Whoa have a shift/reduce or shift/shift conflict
if r > 0:
if r != j:
raise LALRError('Shift/shift conflict in state %d' % st)
raise LALRError(f'Shift/shift conflict in state {st}')
elif r < 0:
# Do a precedence check.
# - if precedence of reduce rule is higher, we reduce.
@ -1462,18 +1460,18 @@ class LRTable(object):
st_action[a] = j
st_actionp[a] = p
if not rlevel:
descrip.append(' ! shift/reduce conflict for %s resolved as shift' % a)
descrip.append(f' ! shift/reduce conflict for {a} resolved as shift')
self.sr_conflicts.append((st, a, 'shift'))
elif (slevel == rlevel) and (rprec == 'nonassoc'):
st_action[a] = None
else:
# Hmmm. Guess we'll keep the reduce
if not slevel and not rlevel:
descrip.append(' ! shift/reduce conflict for %s resolved as reduce' % a)
descrip.append(f' ! shift/reduce conflict for {a} resolved as reduce')
self.sr_conflicts.append((st, a, 'reduce'))
else:
raise LALRError('Unknown conflict in state %d' % st)
raise LALRError(f'Unknown conflict in state {st}')
else:
st_action[a] = j
st_actionp[a] = p
@ -1483,7 +1481,7 @@ class LRTable(object):
for a, p, m in actlist:
if a in st_action:
if p is st_actionp[a]:
descrip.append(' %-15s %s' % (a, m))
descrip.append(f' {a:<15s} {m}')
_actprint[(a, m)] = 1
descrip.append('')
@ -1498,7 +1496,7 @@ class LRTable(object):
j = self.lr0_cidhash.get(id(g), -1)
if j >= 0:
st_goto[n] = j
descrip.append(' %-30s shift and go to state %d' % (n, j))
descrip.append(f' {n:<30s} shift and go to state {j}')
action[st] = st_action
actionp[st] = st_actionp
@ -1518,20 +1516,20 @@ class LRTable(object):
out.append('\nConflicts:\n')
for state, tok, resolution in self.sr_conflicts:
out.append('shift/reduce conflict for %s in state %d resolved as %s' % (tok, state, resolution))
out.append(f'shift/reduce conflict for {tok} in state {state} resolved as {resolution}')
already_reported = set()
for state, rule, rejected in self.rr_conflicts:
if (state, id(rule), id(rejected)) in already_reported:
continue
out.append('reduce/reduce conflict in state %d resolved using rule (%s)' % (state, rule))
out.append('rejected rule (%s) in state %d' % (rejected, state))
out.append(f'reduce/reduce conflict in state {state} resolved using rule {rule}')
out.append(f'rejected rule ({rejected}) in state {state}')
already_reported.add((state, id(rule), id(rejected)))
warned_never = set()
for state, rule, rejected in self.rr_conflicts:
if not rejected.reduced and (rejected not in warned_never):
out.append('Rule (%s) is never reduced' % rejected)
out.append(f'Rule ({rejected}) is never reduced')
warned_never.add(rejected)
return '\n'.join(out)
@ -1618,11 +1616,11 @@ class Parser(metaclass=ParserMeta):
for level, p in enumerate(cls.precedence, start=1):
if not isinstance(p, (list, tuple)):
cls.log.error('Bad precedence table entry %r. Must be a list or tuple', p)
cls.log.error(f'Bad precedence table entry {p!r}. Must be a list or tuple')
return False
if len(p) < 2:
cls.log.error('Malformed precedence entry %s. Must be (assoc, term, ..., term)', p)
cls.log.error(f'Malformed precedence entry {p!r}. Must be (assoc, term, ..., term)')
return False
if not all(isinstance(term, str) for term in p):
@ -1688,7 +1686,7 @@ class Parser(metaclass=ParserMeta):
undefined_symbols = grammar.undefined_symbols()
for sym, prod in undefined_symbols:
cls.log.error('%s:%d: Symbol %r used, but not defined as a token or a rule', prod.file, prod.line, sym)
cls.log.error(f'%s:%d: Symbol %r used, but not defined as a token or a rule', prod.file, prod.line, sym)
fail = True
unused_terminals = grammar.unused_terminals()
@ -1802,9 +1800,9 @@ class Parser(metaclass=ParserMeta):
if token:
lineno = getattr(token, 'lineno', 0)
if lineno:
sys.stderr.write('yacc: Syntax error at line %d, token=%s\n' % (lineno, token.type))
sys.stderr.write(f'yacc: Syntax error at line {lineno}, token={token.type}\n')
else:
sys.stderr.write('yacc: Syntax error, token=%s' % token.type)
sys.stderr.write(f'yacc: Syntax error, token={token.type}')
else:
sys.stderr.write('yacc: Parse error in input. EOF\n')