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Switch to f-strings

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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 SLY (Sly Lex-Yacc) Version 0.0
Copyright (C) 2016 Copyright (C) 2016-2017
David M. Beazley (Dabeaz LLC) David M. Beazley (Dabeaz LLC)
All rights reserved. All rights reserved.
@ -37,7 +37,7 @@ USE AT YOUR OWN RISK.
Requirements 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. of Python are not supported.
Introduction Introduction

2
example/calc/calc.py
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@ -64,7 +64,7 @@ class CalcParser(Parser):
def expr(self, p): def expr(self, p):
return p.term return p.term
@_('term TIMES factor1') @_('term TIMES factor')
def term(self, p): def term(self, p):
return p.term * p.factor 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') __slots__ = ('type', 'value', 'lineno', 'index')
def __repr__(self): 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): class LexerMetaDict(OrderedDict):
''' '''
@ -78,7 +78,7 @@ class LexerMetaDict(OrderedDict):
if callable(value): if callable(value):
value.pattern = self[key] value.pattern = self[key]
else: else:
raise AttributeError('Name %s redefined' % (key)) raise AttributeError(f'Name {key} redefined')
super().__setitem__(key, value) super().__setitem__(key, value)
@ -92,7 +92,7 @@ class LexerMeta(type):
def _(pattern, *extra): def _(pattern, *extra):
patterns = [pattern, *extra] patterns = [pattern, *extra]
def decorate(func): def decorate(func):
pattern = '|'.join('(%s)' % pat for pat in patterns ) pattern = '|'.join(f'({pat})' for pat in patterns )
if hasattr(func, 'pattern'): if hasattr(func, 'pattern'):
func.pattern = pattern + '|' + func.pattern func.pattern = pattern + '|' + func.pattern
else: else:
@ -140,7 +140,7 @@ class Lexer(metaclass=LexerMeta):
Validate the rules to make sure they look sane. Validate the rules to make sure they look sane.
''' '''
if 'tokens' not in vars(cls): 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._token_names = cls._token_names | set(cls.tokens)
cls._literals = cls._literals | set(cls.literals) cls._literals = cls._literals | set(cls.literals)
@ -161,17 +161,17 @@ class Lexer(metaclass=LexerMeta):
cls._token_funcs[tokname] = value cls._token_funcs[tokname] = value
# Form the regular expression component # Form the regular expression component
part = '(?P<%s>%s)' % (tokname, pattern) part = f'(?P<{tokname}>{pattern})'
# Make sure the individual regex compiles properly # Make sure the individual regex compiles properly
try: try:
cpat = re.compile(part, cls.reflags) cpat = re.compile(part, cls.reflags)
except Exception as e: 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 # Verify that the pattern doesn't match the empty string
if cpat.match(''): 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) parts.append(part)
@ -187,7 +187,7 @@ class Lexer(metaclass=LexerMeta):
raise LexerBuildError('ignore specifier must be a string') raise LexerBuildError('ignore specifier must be a string')
if not all(isinstance(lit, str) for lit in cls.literals): 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): def tokenize(self, text, lineno=1, index=0):
# Local copies of frequently used values # 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 # Default implementations of the error handler. May be changed in subclasses
def error(self, value): 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 # sly: yacc.py
# #
# Copyright (C) 2016 # Copyright (C) 2016-2017
# David M. Beazley (Dabeaz LLC) # David M. Beazley (Dabeaz LLC)
# All rights reserved. # All rights reserved.
# #
@ -224,7 +224,7 @@ class Production(object):
if self.prod: if self.prod:
s = '%s -> %s' % (self.name, ' '.join(self.prod)) s = '%s -> %s' % (self.name, ' '.join(self.prod))
else: else:
s = '%s -> <empty>' % self.name s = f'{self.name} -> <empty>'
if self.prec[1]: if self.prec[1]:
s += ' [precedence=%s, level=%d]' % self.prec s += ' [precedence=%s, level=%d]' % self.prec
@ -232,7 +232,7 @@ class Production(object):
return s return s
def __repr__(self): def __repr__(self):
return 'Production(' + str(self) + ')' return f'Production({self})'
def __len__(self): def __len__(self):
return len(self.prod) return len(self.prod)
@ -300,11 +300,11 @@ class LRItem(object):
if self.prod: if self.prod:
s = '%s -> %s' % (self.name, ' '.join(self.prod)) s = '%s -> %s' % (self.name, ' '.join(self.prod))
else: else:
s = '%s -> <empty>' % self.name s = f'{self.name} -> <empty>'
return s return s
def __repr__(self): def __repr__(self):
return 'LRItem(' + str(self) + ')' return f'LRItem({self})'
# ----------------------------------------------------------------------------- # -----------------------------------------------------------------------------
# rightmost_terminal() # rightmost_terminal()
@ -384,7 +384,7 @@ class Grammar(object):
def set_precedence(self, term, assoc, level): def set_precedence(self, term, assoc, level):
assert self.Productions == [None], 'Must call set_precedence() before add_production()' assert self.Productions == [None], 'Must call set_precedence() before add_production()'
if term in self.Precedence: 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']: if assoc not in ['left', 'right', 'nonassoc']:
raise GrammarError("Associativity must be one of 'left','right', or 'nonassoc'") raise GrammarError("Associativity must be one of 'left','right', or 'nonassoc'")
self.Precedence[term] = (assoc, level) self.Precedence[term] = (assoc, level)
@ -409,17 +409,16 @@ class Grammar(object):
def add_production(self, prodname, syms, func=None, file='', line=0): def add_production(self, prodname, syms, func=None, file='', line=0):
if prodname in self.Terminals: 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': 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 # Look for literal tokens
for n, s in enumerate(syms): for n, s in enumerate(syms):
if s[0] in "'\"" and s[0] == s[-1]: if s[0] in "'\"" and s[0] == s[-1]:
c = s[1:-1] c = s[1:-1]
if (len(c) != 1): if (len(c) != 1):
raise GrammarError('%s:%d: Literal token %s in rule %r may only be a single character' % raise GrammarError(f'{file}:{line}: Literal token {s} in rule {prodname!r} may only be a single character')
(file, line, s, prodname))
if c not in self.Terminals: if c not in self.Terminals:
self.Terminals[c] = [] self.Terminals[c] = []
syms[n] = c syms[n] = c
@ -428,14 +427,13 @@ class Grammar(object):
# Determine the precedence level # Determine the precedence level
if '%prec' in syms: if '%prec' in syms:
if syms[-1] == '%prec': 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': if syms[-2] != '%prec':
raise GrammarError('%s:%d: Syntax error. %%prec can only appear at the end of a grammar rule' % raise GrammarError(f'{file}:{line}: Syntax error. %prec can only appear at the end of a grammar rule')
(file, line))
precname = syms[-1] precname = syms[-1]
prodprec = self.Precedence.get(precname) prodprec = self.Precedence.get(precname)
if not prodprec: 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: else:
self.UsedPrecedence.add(precname) self.UsedPrecedence.add(precname)
del syms[-2:] # Drop %prec from the rule del syms[-2:] # Drop %prec from the rule
@ -448,8 +446,8 @@ class Grammar(object):
map = '%s -> %s' % (prodname, syms) map = '%s -> %s' % (prodname, syms)
if map in self.Prodmap: if map in self.Prodmap:
m = self.Prodmap[map] m = self.Prodmap[map]
raise GrammarError('%s:%d: Duplicate rule %s. ' % (file, line, m) + raise GrammarError(f'{file}:{line}: Duplicate rule {m}. ' +
'Previous definition at %s:%d' % (m.file, m.line)) f'Previous definition at {m.file}:{m.line}')
# From this point on, everything is valid. Create a new Production instance # From this point on, everything is valid. Create a new Production instance
pnumber = len(self.Productions) pnumber = len(self.Productions)
@ -488,7 +486,7 @@ class Grammar(object):
start = self.Productions[1].name start = self.Productions[1].name
if start not in self.Nonterminals: 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.Productions[0] = Production(0, "S'", [start])
self.Nonterminals[start].append(0) self.Nonterminals[start].append(0)
self.Start = start self.Start = start
@ -820,13 +818,13 @@ class Grammar(object):
out = [] out = []
out.append('Grammar:\n') out.append('Grammar:\n')
for n, p in enumerate(self.Productions): 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() unused_terminals = self.unused_terminals()
if unused_terminals: if unused_terminals:
out.append('\nUnused terminals:\n') out.append('\nUnused terminals:\n')
for term in unused_terminals: for term in unused_terminals:
out.append(' %s' % term) out.append(f' {term}')
out.append('\nTerminals, with rules where they appear:\n') out.append('\nTerminals, with rules where they appear:\n')
for term in sorted(self.Terminals): for term in sorted(self.Terminals):
@ -1368,9 +1366,9 @@ class LRTable(object):
st_actionp = {} st_actionp = {}
st_goto = {} st_goto = {}
descrip.append('\nstate %d\n' % st) descrip.append(f'\nstate {st}\n')
for p in I: for p in I:
descrip.append(' (%d) %s' % (p.number, p)) descrip.append(f' ({p.number}) {p}')
for p in I: for p in I:
if p.len == p.lr_index + 1: if p.len == p.lr_index + 1:
@ -1382,7 +1380,7 @@ class LRTable(object):
# We are at the end of a production. Reduce! # We are at the end of a production. Reduce!
laheads = p.lookaheads[st] laheads = p.lookaheads[st]
for a in laheads: 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) r = st_action.get(a)
if r is not None: if r is not None:
# Have a shift/reduce or reduce/reduce conflict # Have a shift/reduce or reduce/reduce conflict
@ -1402,7 +1400,7 @@ class LRTable(object):
st_action[a] = -p.number st_action[a] = -p.number
st_actionp[a] = p st_actionp[a] = p
if not slevel and not rlevel: 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')) self.sr_conflicts.append((st, a, 'reduce'))
Productions[p.number].reduced += 1 Productions[p.number].reduced += 1
elif (slevel == rlevel) and (rprec == 'nonassoc'): elif (slevel == rlevel) and (rprec == 'nonassoc'):
@ -1410,7 +1408,7 @@ class LRTable(object):
else: else:
# Hmmm. Guess we'll keep the shift # Hmmm. Guess we'll keep the shift
if not rlevel: 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')) self.sr_conflicts.append((st, a, 'shift'))
elif r < 0: elif r < 0:
# Reduce/reduce conflict. In this case, we favor the rule # 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)' % descrip.append(' ! reduce/reduce conflict for %s resolved using rule %d (%s)' %
(a, st_actionp[a].number, st_actionp[a])) (a, st_actionp[a].number, st_actionp[a]))
else: else:
raise LALRError('Unknown conflict in state %d' % st) raise LALRError(f'Unknown conflict in state {st}')
else: else:
st_action[a] = -p.number st_action[a] = -p.number
st_actionp[a] = p st_actionp[a] = p
@ -1442,13 +1440,13 @@ class LRTable(object):
j = self.lr0_cidhash.get(id(g), -1) j = self.lr0_cidhash.get(id(g), -1)
if j >= 0: if j >= 0:
# We are in a shift state # 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) r = st_action.get(a)
if r is not None: if r is not None:
# Whoa have a shift/reduce or shift/shift conflict # Whoa have a shift/reduce or shift/shift conflict
if r > 0: if r > 0:
if r != j: if r != j:
raise LALRError('Shift/shift conflict in state %d' % st) raise LALRError(f'Shift/shift conflict in state {st}')
elif r < 0: elif r < 0:
# Do a precedence check. # Do a precedence check.
# - if precedence of reduce rule is higher, we reduce. # - if precedence of reduce rule is higher, we reduce.
@ -1462,18 +1460,18 @@ class LRTable(object):
st_action[a] = j st_action[a] = j
st_actionp[a] = p st_actionp[a] = p
if not rlevel: 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')) self.sr_conflicts.append((st, a, 'shift'))
elif (slevel == rlevel) and (rprec == 'nonassoc'): elif (slevel == rlevel) and (rprec == 'nonassoc'):
st_action[a] = None st_action[a] = None
else: else:
# Hmmm. Guess we'll keep the reduce # Hmmm. Guess we'll keep the reduce
if not slevel and not rlevel: 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')) self.sr_conflicts.append((st, a, 'reduce'))
else: else:
raise LALRError('Unknown conflict in state %d' % st) raise LALRError(f'Unknown conflict in state {st}')
else: else:
st_action[a] = j st_action[a] = j
st_actionp[a] = p st_actionp[a] = p
@ -1483,7 +1481,7 @@ class LRTable(object):
for a, p, m in actlist: for a, p, m in actlist:
if a in st_action: if a in st_action:
if p is st_actionp[a]: if p is st_actionp[a]:
descrip.append(' %-15s %s' % (a, m)) descrip.append(f' {a:<15s} {m}')
_actprint[(a, m)] = 1 _actprint[(a, m)] = 1
descrip.append('') descrip.append('')
@ -1498,7 +1496,7 @@ class LRTable(object):
j = self.lr0_cidhash.get(id(g), -1) j = self.lr0_cidhash.get(id(g), -1)
if j >= 0: if j >= 0:
st_goto[n] = j 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 action[st] = st_action
actionp[st] = st_actionp actionp[st] = st_actionp
@ -1518,20 +1516,20 @@ class LRTable(object):
out.append('\nConflicts:\n') out.append('\nConflicts:\n')
for state, tok, resolution in self.sr_conflicts: 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() already_reported = set()
for state, rule, rejected in self.rr_conflicts: for state, rule, rejected in self.rr_conflicts:
if (state, id(rule), id(rejected)) in already_reported: if (state, id(rule), id(rejected)) in already_reported:
continue continue
out.append('reduce/reduce conflict in state %d resolved using rule (%s)' % (state, rule)) out.append(f'reduce/reduce conflict in state {state} resolved using rule {rule}')
out.append('rejected rule (%s) in state %d' % (rejected, state)) out.append(f'rejected rule ({rejected}) in state {state}')
already_reported.add((state, id(rule), id(rejected))) already_reported.add((state, id(rule), id(rejected)))
warned_never = set() warned_never = set()
for state, rule, rejected in self.rr_conflicts: for state, rule, rejected in self.rr_conflicts:
if not rejected.reduced and (rejected not in warned_never): 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) warned_never.add(rejected)
return '\n'.join(out) return '\n'.join(out)
@ -1618,11 +1616,11 @@ class Parser(metaclass=ParserMeta):
for level, p in enumerate(cls.precedence, start=1): for level, p in enumerate(cls.precedence, start=1):
if not isinstance(p, (list, tuple)): 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 return False
if len(p) < 2: 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 return False
if not all(isinstance(term, str) for term in p): if not all(isinstance(term, str) for term in p):
@ -1688,7 +1686,7 @@ class Parser(metaclass=ParserMeta):
undefined_symbols = grammar.undefined_symbols() undefined_symbols = grammar.undefined_symbols()
for sym, prod in 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 fail = True
unused_terminals = grammar.unused_terminals() unused_terminals = grammar.unused_terminals()
@ -1802,9 +1800,9 @@ class Parser(metaclass=ParserMeta):
if token: if token:
lineno = getattr(token, 'lineno', 0) lineno = getattr(token, 'lineno', 0)
if lineno: 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: else:
sys.stderr.write('yacc: Syntax error, token=%s' % token.type) sys.stderr.write(f'yacc: Syntax error, token={token.type}')
else: else:
sys.stderr.write('yacc: Parse error in input. EOF\n') sys.stderr.write('yacc: Parse error in input. EOF\n')