/
lexer_def.py
935 lines (746 loc) · 27.7 KB
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lexer_def.py
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"""
lexer_def.py -- A lexer for both shell and Oil.
It consists of a series of lexer modes, each with a regex -> Id mapping.
After changing this file, run:
build/dev.sh all
or at least:
build/dev.sh fastlex
Input Handling
--------------
Every line is NUL terminated:
'one\n\0' 'last line\0'
which means that no regexes below should match \0. The core/lexer_gen.py code
generator adds and extra rule for \0.
For example, use [^'\0]+ instead of [^']+ .
If this rule isn't followed, we would read unitialized memory past the
sentinel. Python's regex engine knows where the end of the input string is, so
it doesn't require need a sentinel like \0.
"""
from _devbuild.gen.id_kind_asdl import Id, Id_t, Kind
from _devbuild.gen.types_asdl import lex_mode_e
from frontend import id_kind_def
from typing import Tuple
# Initialize spec that the lexer depends on.
# NOTE: This is duplicated in frontend/id_kind_gen.py.
ID_SPEC = id_kind_def.IdSpec({}, {})
id_kind_def.AddKinds(ID_SPEC)
id_kind_def.AddBoolKinds(ID_SPEC) # must come second
id_kind_def.SetupTestBuiltin(ID_SPEC, {}, {}, {})
def C(pat, tok_type):
# type: (str, Id_t) -> Tuple[bool, str, Id_t]
""" Lexer rule with a constant string, e.g. C('$*', VSub_Star) """
return (False, pat, tok_type)
def R(pat, tok_type):
# type: (str, Id_t) -> Tuple[bool, str, Id_t]
""" Lexer rule with a regex string, e.g. R('\$[0-9]', VSub_Number) """
return (True, pat, tok_type)
# See unit tests in frontend/match_test.py.
# We need the [^\0]* because the re2c translation assumes it's anchored like $.
SHOULD_HIJACK_RE = r'#!.*sh[ \t\r\n][^\0]*'
_SIGNIFICANT_SPACE = R(r'[ \t\r]+', Id.WS_Space)
_BACKSLASH = [
R(r'\\[^\n\0]', Id.Lit_EscapedChar),
C('\\\n', Id.Ignored_LineCont),
]
# Only 4 characters are backslash escaped inside "".
# https://www.gnu.org/software/bash/manual/bash.html#Double-Quotes
_DQ_BACKSLASH = [
R(r'\\[$`"\\]', Id.Lit_EscapedChar)
]
VAR_NAME_RE = r'[a-zA-Z_][a-zA-Z0-9_]*'
# All Kind.VSub
_VARS = [
# Unbraced variables
R(r'\$' + VAR_NAME_RE, Id.VSub_DollarName),
R(r'\$[0-9]', Id.VSub_Number),
C(r'$!', Id.VSub_Bang),
C(r'$@', Id.VSub_At),
C(r'$#', Id.VSub_Pound),
C(r'$$', Id.VSub_Dollar),
C(r'$*', Id.VSub_Star),
C(r'$-', Id.VSub_Hyphen),
C(r'$?', Id.VSub_QMark),
]
# Kind.Left that are valid in double-quoted modes.
_LEFT_SUBS = [
C('`', Id.Left_Backtick),
C('$(', Id.Left_DollarParen),
C('${', Id.Left_DollarBrace),
C('$((', Id.Left_DollarDParen),
C('$[', Id.Left_DollarBracket),
]
# Additional Kind.Left that are valid in unquoted modes.
_LEFT_UNQUOTED = [
C('"', Id.Left_DoubleQuote),
C("'", Id.Left_SingleQuoteRaw),
C('$"', Id.Left_DollarDoubleQuote),
C("$'", Id.Left_SingleQuoteC),
C('<(', Id.Left_ProcSubIn),
C('>(', Id.Left_ProcSubOut),
]
# The regexes below are in Python syntax, but are translate to re2c syntax by
# frontend/lexer_gen.py.
#
# http://re2c.org/manual/syntax/syntax.html
# https://docs.python.org/2/library/re.html
#
# We use a limited set of constructs:
# - + and * for repetition
# - Character classes [] with simple ranges and negation
# - Escapes like \n \0
LEXER_DEF = {} # TODO: Should be a list so we enforce order.
# Anything until the end of the line is a comment. Does not match the newline
# itself. We want to switch modes and possibly process Op_Newline for here
# docs, etc.
LEXER_DEF[lex_mode_e.Comment] = [
R(r'[^\n\0]*', Id.Ignored_Comment)
]
# A whitelist for efficiency. The shell language says that "anything else" is
# a literal character. In other words, a single $ \ or ! is a literal, not a
# syntax error. It's defined negatively, but let's define positive runs here.
# TODO: Add + and @ here they are never special? It's different for Oil
# though.
# The range \x80-\xff makes sure that UTF-8 sequences are a single token.
_LITERAL_WHITELIST_REGEX = r'[\x80-\xffa-zA-Z0-9_/.\-]+'
_UNQUOTED = _BACKSLASH + _LEFT_SUBS + _LEFT_UNQUOTED + _VARS + [
# NOTE: We could add anything 128 and above to this character class? So
# utf-8 characters don't get split?
R(_LITERAL_WHITELIST_REGEX, Id.Lit_Chars),
# For tilde expansion. The list of chars is Lit_Chars, but WITHOUT the /. We
# want the next token after the tilde TildeLike token start with a /.
# NOTE: Happens in both ShCommand and DBracket modes.
R(r'~[a-zA-Z0-9_.-]*', Id.Lit_TildeLike),
C('#', Id.Lit_Pound), # For comments
_SIGNIFICANT_SPACE,
C('\n', Id.Op_Newline),
C('&', Id.Op_Amp),
C('|', Id.Op_Pipe),
C('|&', Id.Op_PipeAmp),
C('&&', Id.Op_DAmp),
C('||', Id.Op_DPipe),
C(';', Id.Op_Semi),
C(';;', Id.Op_DSemi),
C('(', Id.Op_LParen),
C(')', Id.Op_RParen),
R(r'[^\0]', Id.Lit_Other), # any other single char is a literal
]
# In ShCommand and DBracket states.
_EXTGLOB_BEGIN = [
C('@(', Id.ExtGlob_At),
C('*(', Id.ExtGlob_Star),
C('+(', Id.ExtGlob_Plus),
C('?(', Id.ExtGlob_QMark),
C('!(', Id.ExtGlob_Bang),
]
_KEYWORDS = [
# NOTE: { is matched elsewhere
C('[[', Id.KW_DLeftBracket),
C('!', Id.KW_Bang),
C('for', Id.KW_For),
C('while', Id.KW_While),
C('until', Id.KW_Until),
C('do', Id.KW_Do),
C('done', Id.KW_Done),
C('in', Id.KW_In),
C('case', Id.KW_Case),
C('esac', Id.KW_Esac),
C('if', Id.KW_If),
C('fi', Id.KW_Fi),
C('then', Id.KW_Then),
C('else', Id.KW_Else),
C('elif', Id.KW_Elif),
C('function', Id.KW_Function),
C('time', Id.KW_Time),
# Oil integration
C('const', Id.KW_Const),
C('var', Id.KW_Var),
C('setvar', Id.KW_SetVar),
C('setref', Id.KW_SetRef),
C('set', Id.KW_Set),
C('setlocal', Id.KW_SetLocal),
C('setglobal', Id.KW_SetGlobal),
C('proc', Id.KW_Proc),
# Not used, but reserved for now?
C('pass', Id.KW_Pass),
C('func', Id.KW_Func),
]
# These are treated like builtins in bash, but keywords in OSH. However, we
# maintain compatibility with bash for the 'type' builtin.
_CONTROL_FLOW = [
C('break', Id.ControlFlow_Break),
C('continue', Id.ControlFlow_Continue),
C('return', Id.ControlFlow_Return),
C('exit', Id.ControlFlow_Exit),
]
# Used by oil_lang/grammar_gen.py too
EXPR_WORDS = [
C('null', Id.Expr_Null),
C('true', Id.Expr_True),
C('false', Id.Expr_False),
C('div', Id.Expr_Div),
C('mod', Id.Expr_Mod),
C('xor', Id.Expr_Xor),
C('and', Id.Expr_And),
C('or', Id.Expr_Or),
C('not', Id.Expr_Not),
C('for', Id.Expr_For),
C('is', Id.Expr_Is),
C('in', Id.Expr_In),
C('if', Id.Expr_If),
C('else', Id.Expr_Else),
# for function literals
C('func', Id.Expr_Func),
# TODO: as ?
# expr as List[Int] for casting? Or just cast(List[Int]], expr)?
# What about specifying types without casting? 'of'?
]
# The 'compen' and 'type' builtins introspect on keywords and builtins.
OSH_KEYWORD_NAMES = [name for _, name, _ in _KEYWORDS]
OSH_KEYWORD_NAMES.append('{') # not in our lexer list
_CF_NAMES = [name for _, name, _ in _CONTROL_FLOW]
def IsControlFlow(name):
# type: (str) -> bool
return name in _CF_NAMES
def IsKeyword(name):
# type: (str) -> bool
return name in OSH_KEYWORD_NAMES
FD_VAR_NAME = r'\{' + VAR_NAME_RE + r'\}'
# file descriptors can only have two digits, like mksh
# dash/zsh/etc. can have one
FD_NUM = r'[0-9]?[0-9]?'
# These two can must be recognized in the Outer state, but can't nested within
# [[.
# Keywords have to be checked before _UNQUOTED so we get <KW_If "if"> instead
# of <Lit_Chars "if">.
LEXER_DEF[lex_mode_e.ShCommand] = [
# These four are not allowed within [[, so they are in ShCommand but not
# _UNQUOTED.
# e.g. beginning of NAME=val, which will always be longer than
# _LITERAL_WHITELIST_REGEX.
R(VAR_NAME_RE + '\+?=', Id.Lit_VarLike),
R(VAR_NAME_RE + '\[', Id.Lit_ArrayLhsOpen),
R(r'\]\+?=', Id.Lit_ArrayLhsClose),
C('((', Id.Op_DLeftParen),
# For static globbing, and [] for array literals
C('[', Id.Lit_LBracket), # e.g. A=(['x']=1)
C(']', Id.Lit_RBracket), # e.g. *.[ch]
# NOTE: Glob_Star and Glob_QMark are for dynamic parsing
C('*', Id.Lit_Star),
C('?', Id.Lit_QMark),
# For brace expansion {a,b}
C('{', Id.Lit_LBrace),
C('}', Id.Lit_RBrace), # Also for var sub ${a}
C(',', Id.Lit_Comma),
C('=', Id.Lit_Equals), # for x = 1+2*3
# @array and @func(1, c)
R('@' + VAR_NAME_RE, Id.Lit_Splice), # for Oil splicing
R(FD_NUM + r'<', Id.Redir_Less),
R(FD_NUM + r'>', Id.Redir_Great),
R(FD_NUM + r'<<', Id.Redir_DLess),
R(FD_NUM + r'<<<', Id.Redir_TLess),
R(FD_NUM + r'>>', Id.Redir_DGreat),
R(FD_NUM + r'<<-', Id.Redir_DLessDash),
R(FD_NUM + r'>&', Id.Redir_GreatAnd),
R(FD_NUM + r'<&', Id.Redir_LessAnd),
R(FD_NUM + r'<>', Id.Redir_LessGreat),
R(FD_NUM + r'>\|', Id.Redir_Clobber),
R(FD_VAR_NAME + r'<', Id.Redir_Less),
R(FD_VAR_NAME + r'>', Id.Redir_Great),
R(FD_VAR_NAME + r'<<', Id.Redir_DLess),
R(FD_VAR_NAME + r'<<<', Id.Redir_TLess),
R(FD_VAR_NAME + r'>>', Id.Redir_DGreat),
R(FD_VAR_NAME + r'<<-', Id.Redir_DLessDash),
R(FD_VAR_NAME + r'>&', Id.Redir_GreatAnd),
R(FD_VAR_NAME + r'<&', Id.Redir_LessAnd),
R(FD_VAR_NAME + r'<>', Id.Redir_LessGreat),
R(FD_VAR_NAME + r'>\|', Id.Redir_Clobber),
# No leading descriptor (2 is implied)
C(r'&>', Id.Redir_AndGreat),
C(r'&>>', Id.Redir_AndDGreat),
] + _KEYWORDS + _CONTROL_FLOW + _UNQUOTED + _EXTGLOB_BEGIN
# Preprocessing before Outer
LEXER_DEF[lex_mode_e.Backtick] = [
C(r'`', Id.Backtick_Right),
# A backslash, and then one of the SAME FOUR escaped chars in the DQ mode.
R(r'\\[$`"\\]', Id.Backtick_Quoted),
R(r'[^`\\\0]+', Id.Backtick_Other), # contiguous run of literals
R(r'[^\0]', Id.Backtick_Other), # anything else
]
# DBRACKET: can be like Outer, except:
# - Don't really need redirects either... Redir_Less could be Op_Less
# - Id.Op_DLeftParen can't be nested inside.
LEXER_DEF[lex_mode_e.DBracket] = [
C(']]', Id.Lit_DRightBracket),
# Must be KW and not Op, because we can have stuff like [[ $foo == !* ]]
# in addition to [[ ! a && b ]]
C('!', Id.KW_Bang),
C('<', Id.Op_Less),
C('>', Id.Op_Great),
] + ID_SPEC.LexerPairs(Kind.BoolUnary) + \
ID_SPEC.LexerPairs(Kind.BoolBinary) + \
_UNQUOTED + _EXTGLOB_BEGIN
# Inside an extended glob, most characters are literals, including spaces and
# punctuation. We also accept \, $var, ${var}, "", etc. They can also be
# nested, so _EXTGLOB_BEGIN appears here.
#
# Example: echo @(<> <>|&&|'foo'|$bar)
LEXER_DEF[lex_mode_e.ExtGlob] = \
_BACKSLASH + _LEFT_SUBS + _LEFT_UNQUOTED + _VARS + _EXTGLOB_BEGIN + [
R(r'[^\\$`"\'|)@*+!?\0]+', Id.Lit_Chars),
C('|', Id.Op_Pipe),
C(')', Id.Op_RParen), # maybe be translated to Id.ExtGlob_RParen
R(r'[^\0]', Id.Lit_Other), # everything else is literal
]
# Notes on BASH_REGEX states
#
# From bash manual:
#
# - Any part of the pattern may be quoted to force the quoted portion to be
# matched as a string.
# - Bracket expressions in regular expressions must be treated carefully, since
# normal quoting characters lose their meanings between brackets.
# - If the pattern is stored in a shell variable, quoting the variable
# expansion forces the entire pattern to be matched as a string.
#
# Is there a re.escape function? It's just like EscapeGlob and UnescapeGlob.
#
# TODO: For testing, write a script to extract and save regexes... and compile
# them with regcomp. I've only seen constant regexes.
#
# From code: ( | ) are treated special.
LEXER_DEF[lex_mode_e.BashRegex] = _LEFT_SUBS + _LEFT_UNQUOTED + _VARS + [
# NOTE: bash accounts for spaces and non-word punctuation like ; inside ()
# and []. We will avoid that and ask the user to extract a variable?
R(r'[a-zA-Z0-9_/-]+', Id.Lit_Chars), # not including period
_SIGNIFICANT_SPACE,
# Normally, \x evalutes to x. But quoted regex metacharacters like \* should
# evaluate to \*. Compare with ( | ).
R(r'\\[*+?.^$\[\]]', Id.Lit_RegexMeta),
# Everything else is an escape.
R(r'\\[^\n\0]', Id.Lit_EscapedChar),
C('\\\n', Id.Ignored_LineCont),
# NOTE: ( | and ) aren't operators!
R(r'[^\0]', Id.Lit_Other), # everything else is literal
]
LEXER_DEF[lex_mode_e.DQ] = _DQ_BACKSLASH + [
C('\\\n', Id.Ignored_LineCont),
] + _LEFT_SUBS + _VARS + [
R(r'[^$`"\0\\]+', Id.Lit_Chars), # matches a line at most
# NOTE: When parsing here doc line, this token doesn't end it.
C('"', Id.Right_DoubleQuote),
R(r'[^\0]', Id.Lit_Other), # e.g. "$"
]
_VS_ARG_COMMON = [
C('/', Id.Lit_Slash), # for patsub (not Id.VOp2_Slash)
C('#', Id.Lit_Pound), # for patsub prefix (not Id.VOp1_Pound)
C('%', Id.Lit_Percent), # for patsdub suffix (not Id.VOp1_Percent)
C('}', Id.Right_DollarBrace), # For var sub "${a}"
]
# Kind.{LIT,IGNORED,VS,LEFT,RIGHT,Eof}
LEXER_DEF[lex_mode_e.VSub_ArgUnquoted] = \
_BACKSLASH + _VS_ARG_COMMON + _LEFT_SUBS + _LEFT_UNQUOTED + _VARS + [
# NOTE: added < and > so it doesn't eat <()
R(r'[^$`/}"\'\0\\#%<>]+', Id.Lit_Chars),
R(r'[^\0]', Id.Lit_Other), # e.g. "$", must be last
]
# Kind.{LIT,IGNORED,VS,LEFT,RIGHT,Eof}
LEXER_DEF[lex_mode_e.VSub_ArgDQ] = \
_DQ_BACKSLASH + _VS_ARG_COMMON + _LEFT_SUBS + _VARS + [
C(r'\}', Id.Lit_EscapedChar), # For "${var-\}}"
R(r'[^$`/}"\0\\#%]+', Id.Lit_Chars), # matches a line at most
# Weird wart: even in double quoted state, double quotes are allowed
C('"', Id.Left_DoubleQuote),
# Another weird wart of bash/mksh: $'' is recognized but NOT ''!
C("$'", Id.Left_SingleQuoteC),
R(r'[^\0]', Id.Lit_Other), # e.g. "$", must be last
]
# NOTE: Id.Ignored_LineCont is NOT supported in SQ state, as opposed to DQ
# state.
LEXER_DEF[lex_mode_e.SQ_Raw] = [
R(r"[^'\0]+", Id.Lit_Chars), # matches a line at most
C("'", Id.Right_SingleQuote),
]
# The main purpose for EXPR_CHARS is in regex literals, e.g. [a-z \t \n].
#
# Since chars are integers, means that \u1234 is the same as 0x1234. And 0x0
# In Python:
# chr(0x00012345) == u'\u00012345'
#
# In Oil:
#
# 0x00012345 == \u00012345
# chr(0x00012345) == chr(\u00012345) == c'\u00012345'
#
# The syntax follows Python, which is stricter than bash. There must be
# exactly 2, 4, or 8 digits.
EXPR_CHARS = [
# This is like Rust. We don't have the legacy C escapes like \b.
# NOTE: \' and \" are more readable versions of '"' and "'" in regexs
R(r'\\[0rtn\\"%s]' % "'", Id.Char_OneChar),
R(r'\\x[0-9a-fA-F]{2}', Id.Char_Hex),
R(r'\\u[0-9a-fA-F]{4}', Id.Char_Unicode4),
R(r'\\U[0-9a-fA-F]{8}', Id.Char_Unicode8),
]
# Shared between echo -e and $''.
_C_STRING_COMMON = [
# \x6 is valid in bash
R(r'\\x[0-9a-fA-F]{1,2}', Id.Char_Hex),
R(r'\\u[0-9a-fA-F]{1,4}', Id.Char_Unicode4),
R(r'\\U[0-9a-fA-F]{1,8}', Id.Char_Unicode8),
R(r'\\[0abeEfrtnv\\]', Id.Char_OneChar),
# Backslash that ends a line. Note '.' doesn't match a newline character.
C('\\\n', Id.Char_Literals),
# e.g. \A is not an escape, and \x doesn't match a hex escape. We allow it,
# but a lint tool could warn about it.
C('\\', Id.Char_BadBackslash),
]
# Used by ECHO_LEXER in core/builtin.py.
ECHO_E_DEF = _C_STRING_COMMON + [
# Note: tokens above \0377 can either be truncated or be flagged a syntax
# error in strict mode.
R(r'\\0[0-7]{1,3}', Id.Char_Octal4),
C(r'\c', Id.Char_Stop),
# e.g. 'foo', anything that's not a backslash escape
R(r'[^\\\0]+', Id.Char_Literals),
]
OCTAL3_RE = r'\\[0-7]{1,3}'
# https://www.gnu.org/software/bash/manual/html_node/Controlling-the-PromptEvaluator.html#Controlling-the-PromptEvaluator
PS1_DEF = [
R(OCTAL3_RE, Id.PS_Octal3),
R(r'\\[adehHjlnrstT@AuvVwW!#$\\]', Id.PS_Subst),
C(r'\[', Id.PS_LBrace), # non-printing
C(r'\]', Id.PS_RBrace),
R(r'[^\\\0]+', Id.PS_Literals),
# e.g. \x is not a valid escape.
C('\\', Id.PS_BadBackslash),
]
# NOTE: Id.Ignored_LineCont is also not supported here, even though the whole
# point of it is that supports other backslash escapes like \n! It just
# becomes a regular backslash.
LEXER_DEF[lex_mode_e.SQ_C] = _C_STRING_COMMON + [
# Silly difference! In echo -e, the syntax is \0377, but here it's $'\377',
# with no leading 0.
R(OCTAL3_RE, Id.Char_Octal3),
# ' is escaped in $'' mode, but not echo -e. Ditto fr ", not sure why.
C(r"\'", Id.Char_OneChar),
C(r'\"', Id.Char_OneChar),
# e.g. 'foo', anything that's not a backslash escape. Need to exclude ' as
# well.
R(r"[^\\'\0]+", Id.Char_Literals),
C("'", Id.Right_SingleQuote),
# Backslash that ends the file! Caught by re2c exhaustiveness check. Parser
# will assert; should give a better syntax error.
C('\\\0', Id.Unknown_Tok),
]
LEXER_DEF[lex_mode_e.PrintfOuter] = _C_STRING_COMMON + [
R(OCTAL3_RE, Id.Char_Octal3),
R(r"[^%\\\0]+", Id.Char_Literals),
C('%%', Id.Format_EscapedPercent),
C('%', Id.Format_Percent),
]
# Maybe: bash also supports %(strftime)T
LEXER_DEF[lex_mode_e.PrintfPercent] = [
# Flags
R('[- +#]', Id.Format_Flag),
C('0', Id.Format_Zero),
R('[1-9][0-9]*', Id.Format_Num),
C('*', Id.Format_Star),
C('.', Id.Format_Dot),
# We support dsq. The others we parse to display an error message.
R('[disqbcouxXeEfFgG]', Id.Format_Type),
R('\([^()]*\)T', Id.Format_Time),
R(r'[^\0]', Id.Unknown_Tok), # any other char
]
LEXER_DEF[lex_mode_e.VSub_1] = [
R(VAR_NAME_RE, Id.VSub_Name),
# ${11} is valid, compared to $11 which is $1 and then literal 1.
R(r'[0-9]+', Id.VSub_Number),
C('!', Id.VSub_Bang),
C('@', Id.VSub_At),
C('#', Id.VSub_Pound),
C('$', Id.VSub_Dollar),
C('*', Id.VSub_Star),
C('-', Id.VSub_Hyphen),
C('?', Id.VSub_QMark),
C('}', Id.Right_DollarBrace),
C('\\\n', Id.Ignored_LineCont),
C('\n', Id.Unknown_Tok), # newline not allowed inside ${}
R(r'[^\0]', Id.Unknown_Tok), # any char except newline
]
LEXER_DEF[lex_mode_e.VSub_2] = \
ID_SPEC.LexerPairs(Kind.VTest) + \
ID_SPEC.LexerPairs(Kind.VOp0) + \
ID_SPEC.LexerPairs(Kind.VOp1) + \
ID_SPEC.LexerPairs(Kind.VOp2) + \
ID_SPEC.LexerPairs(Kind.VOp3) + [
C('}', Id.Right_DollarBrace),
C('\\\n', Id.Ignored_LineCont),
C('\n', Id.Unknown_Tok), # newline not allowed inside ${}
R(r'[^\0]', Id.Unknown_Tok), # any char except newline
]
_EXPR_ARITH_SHARED = [
C('\\\n', Id.Ignored_LineCont),
R(r'[^\0]', Id.Unknown_Tok) # any char. This should be a syntax error.
]
# https://www.gnu.org/software/bash/manual/html_node/Shell-Arithmetic.html#Shell-Arithmetic
LEXER_DEF[lex_mode_e.Arith] = \
_LEFT_SUBS + _VARS + _LEFT_UNQUOTED + [
# Arithmetic expressions can cross newlines.
R(r'[ \t\r\n]+', Id.Ignored_Space),
# Examples of arith constants:
# 64#azAZ
# 0xabc 0xABC
# 0123
# A separate digits token makes this easier to parse STATICALLY. But this
# doesn't help with DYNAMIC parsing.
R(VAR_NAME_RE, Id.Lit_ArithVarLike), # for variable names or 64#_
R(r'[0-9]+', Id.Lit_Digits),
C('@', Id.Lit_At), # for 64#@ or ${a[@]}
C('#', Id.Lit_Pound), # for 64#a
# TODO: 64#@ interferes with VS_AT. Hm.
] + ID_SPEC.LexerPairs(Kind.Arith) + _EXPR_ARITH_SHARED
# A lexer for the parser that converts globs to extended regexes. Since we're
# only parsing character classes ([^[:space:][:alpha:]]) as opaque blobs, we
# don't need lexer modes here.
GLOB_DEF = [
# These could be operators in the glob, or just literals in a char class,
# e.g. touch '?'; echo [?].
C('*', Id.Glob_Star),
C('?', Id.Glob_QMark),
# For negation. Treated as operators inside [], but literals outside.
C('!', Id.Glob_Bang),
C('^', Id.Glob_Caret),
# Character classes.
C('[', Id.Glob_LBracket),
C(']', Id.Glob_RBracket),
# There is no whitelist of characters; backslashes are unconditionally
# removed. With libc.fnmatch(), the pattern r'\f' matches 'f' but not '\\f'.
# See libc_test.py.
R(r'\\[^\0]', Id.Glob_EscapedChar),
C('\\', Id.Glob_BadBackslash), # Trailing single backslash
# For efficiency, combine other characters into a single token, e.g. 'py' in
# '*.py' or 'alpha' in '[[:alpha:]]'.
R(r'[a-zA-Z0-9_]+', Id.Glob_CleanLiterals), # no regex escaping
R(r'[^\0]', Id.Glob_OtherLiteral), # anything else -- examine the char
]
# History expansion. We're doing this as "pre-lexing" since that's what bash
# and zsh seem to do. Example:
#
# $ foo=x
# $ echo $
# $ !!foo # expands to echo $foo and prints x
#
# We can also reuse this in the RootCompleter to expand history interactively.
#
# bash note: handled in lib/readline/histexpand.c. Quite messy and handles
# quotes AGAIN.
#
# Note: \! gets expanded to literal \! for the real lexer, but no history
# expansion occurs.
HISTORY_DEF = [
# Common operators.
R(r'![!*^$]', Id.History_Op),
# By command number.
R(r'!-?[0-9]+', Id.History_Num),
# Search by prefix of substring (optional '?').
# NOTE: there are no numbers allowed here! Bash doesn't seem to support it.
# No hyphen since it conflits with $-1 too.
#
# Required trailing whitespace is there to avoid conflict with [!charclass]
# and ${!indirect}. This is a simpler hack than the one bash has. See
# frontend/lex_test.py.
R(r'!\??[a-zA-Z_/.][0-9a-zA-Z_/.]+[ \t\r\n]', Id.History_Search),
# Comment is until end of line
R(r"#[^\0]*", Id.History_Other),
# Single quoted, e.g. 'a' or $'\n'. Terminated by another single quote or
# end of string.
R(r"'[^'\0]*'?", Id.History_Other),
# Runs of chars that are definitely not special
R(r"[^!\\'#\0]+", Id.History_Other),
# Escaped characters. \! disables history
R(r'\\[^\0]', Id.History_Other),
# Other single chars, like a trailing \ or !
R(r'[^\0]', Id.History_Other),
]
BRACE_RANGE_DEF = [
R(r'-?[0-9]+', Id.Range_Int),
R(r'[a-zA-Z]', Id.Range_Char), # just a single character
R(r'\.\.', Id.Range_Dots),
R(r'[^\0]', Id.Range_Other), # invalid
]
# Note: this would be an optimization. NUL handling might be a problem
# because the ('\0', Id.Eol_Tok) rule is automatically inserted.
QSN_DEF = [
# Optimized so they appear together
R(_LITERAL_WHITELIST_REGEX, Id.QSN_LiteralBytes),
# includes \r \n \t \0
R(r'[\x00-\x1F\'"\\]', Id.QSN_SpecialByte),
# UTF-8 sequences
R(r'[\xc0-\xdf]', Id.QSN_Begin2),
R(r'[\xe0-\xef]', Id.QSN_Begin3),
R(r'[\xf0-\xf7]', Id.QSN_Begin4),
R(r'[\x80-\xbf]', Id.QSN_Cont),
R(r'[^\0]', Id.QSN_LiteralBytes),
]
#
# Oil lexing. TODO: Move to a different file?
#
# Valid in lex_mode_e.{Expr,DQ_Oil}
# Used by oil_lang/grammar_gen.py
OIL_LEFT_SUBS = [
C('$(', Id.Left_DollarParen),
C('${', Id.Left_DollarBrace),
C('$[', Id.Left_DollarBracket), # Unused now
# For lazily evaluated expressions
C('%(', Id.Expr_Reserved),
C('%{', Id.Expr_Reserved),
C('%[', Id.Expr_Reserved),
]
# Valid in lex_mode_e.Expr
# TODO:
# - raw strings with r' r"
# - multiline strings ''' """ r''' r"""
# Used by oil_lang/grammar_gen.py
OIL_LEFT_UNQUOTED = [
C('"', Id.Left_DoubleQuote),
# In expression mode, we add the r'' and c'' prefixes for '' and $''.
C("'", Id.Left_SingleQuoteRaw),
C("r'", Id.Left_SingleQuoteRaw),
C("c'", Id.Left_SingleQuoteC),
C("$'", Id.Left_SingleQuoteC),
# Not valid in DQ_Oil
C('@(', Id.Left_AtParen), # Legacy shell arrays.
C('@[', Id.Left_AtBracket), # Oil arrays. Not used yet.
C('@{', Id.Expr_Reserved), # For table literals? Not used yet.
]
# Used by oil_lang/grammar_gen.py
EXPR_OPS = [
# Terminator
C(';', Id.Op_Semi),
C('(', Id.Op_LParen),
C(')', Id.Op_RParen),
# NOTE: type expressions are expressions, e.g. Dict[Str, Int]
C('[', Id.Op_LBracket),
C(']', Id.Op_RBracket),
C('{', Id.Op_LBrace),
C('}', Id.Op_RBrace),
]
# Newline is significant, but sometimes elided by expr_parse.py.
_EXPR_NEWLINE_COMMENT = [
C('\n', Id.Op_Newline),
R(r'#[^\n\0]*', Id.Ignored_Comment),
R(r'[ \t\r]+', Id.Ignored_Space),
]
# Python 3 float literals:
# digitpart ::= digit (["_"] digit)*
# fraction ::= "." digitpart
# exponent ::= ("e" | "E") ["+" | "-"] digitpart
# pointfloat ::= [digitpart] fraction | digitpart "."
# exponentfloat ::= (digitpart | pointfloat) exponent
# floatnumber ::= pointfloat | exponentfloat
# This is the same as far as I can tell?
# This is a hand-written re2c rule to "refine" the Id.Expr_Float token to
# include undescores: 1_000.234_567
LEXER_REFINEMENTS = {
(lex_mode_e.Expr, Id.Expr_Float): """
digit = [0-9]
digitpart = digit ("_"? digit)*
fraction = "." digitpart
exponent = ("e" | "E") ("+" | "-")? digitpart
float = digitpart fraction? exponent? | fraction exponent?
"""
}
# TODO: Should all of these be Kind.Op instead of Kind.Arith? And Kind.Expr?
# NOTE: Borrowing tokens from Arith (i.e. $(( )) ), but not using LexerPairs().
LEXER_DEF[lex_mode_e.Expr] = \
_VARS + OIL_LEFT_SUBS + OIL_LEFT_UNQUOTED + EXPR_OPS + EXPR_WORDS + \
EXPR_CHARS + [
# https://docs.python.org/3/reference/lexical_analysis.html#integer-literals
#
# integer ::= decinteger | bininteger | octinteger | hexinteger
# decinteger ::= nonzerodigit (["_"] digit)* | "0"+ (["_"] "0")*
# bininteger ::= "0" ("b" | "B") (["_"] bindigit)+
# octinteger ::= "0" ("o" | "O") (["_"] octdigit)+
# hexinteger ::= "0" ("x" | "X") (["_"] hexdigit)+
# nonzerodigit ::= "1"..."9"
# digit ::= "0"..."9"
# bindigit ::= "0" | "1"
# octdigit ::= "0"..."7"
# hexdigit ::= digit | "a"..."f" | "A"..."F"
# Python allows 0 to be written 00 or 0_0_0, which is weird.
C('0', Id.Expr_DecInt),
R(r'[1-9](_?[0-9])*', Id.Expr_DecInt),
R(r'0[bB](_?[01])+', Id.Expr_BinInt),
R(r'0[oO](_?[0-7])+', Id.Expr_OctInt),
R(r'0[xX](_?[0-9a-fA-F])+', Id.Expr_HexInt),
# !!! This is REFINED by a hand-written re2c rule !!!
# The dev build is slightly different than the production build.
R(r'[0-9]+(\.[0-9]*)?([eE][+\-]?[0-9]+)?', Id.Expr_Float),
# These can be looked up as keywords separately, so you enforce that they have
# space around them?
R(VAR_NAME_RE, Id.Expr_Name),
R('%' + VAR_NAME_RE, Id.Expr_Symbol),
#
# Arith
#
C(',', Id.Arith_Comma),
C(':', Id.Arith_Colon), # for slicing a[1:2]
C('?', Id.Arith_QMark), # regex postfix
C('+', Id.Arith_Plus), # arith infix, regex postfix
C('-', Id.Arith_Minus), # arith infix, regex postfix
C('*', Id.Arith_Star),
C('^', Id.Arith_Caret), # ^ rather than ** is exponentiation. xor is 'xor'.
C('/', Id.Arith_Slash),
C('<', Id.Arith_Less),
C('>', Id.Arith_Great),
C('<=', Id.Arith_LessEqual),
C('>=', Id.Arith_GreatEqual),
C('==', Id.Arith_DEqual),
C('!=', Id.Arith_NEqual),
# Bitwise operators
C('&', Id.Arith_Amp),
C('|', Id.Arith_Pipe),
C('>>', Id.Arith_DGreat),
C('<<', Id.Arith_DLess), # Doesn't Java also have <<< ?
# Bitwise complement, as well as infix pattern matching
C('~', Id.Arith_Tilde),
C('!~', Id.Expr_NotTilde),
# Left out for now:
# ++ -- -- needed for loops, awk?
# ! && || -- needed for find dialect
# = += etc.
C('=', Id.Arith_Equal),
C('+=', Id.Arith_PlusEqual),
C('-=', Id.Arith_MinusEqual),
C('*=', Id.Arith_StarEqual),
C('/=', Id.Arith_SlashEqual),
C('%=', Id.Arith_PercentEqual),
C('&=', Id.Arith_AmpEqual),
C('|=', Id.Arith_PipeEqual),
C('^=', Id.Arith_CaretEqual), # Exponentiation
C('>>=', Id.Arith_DGreatEqual),
C('<<=', Id.Arith_DLessEqual),
#
# Expr
#
C('.', Id.Expr_Dot), # attribute access (static or dynamic)
C('::', Id.Expr_DColon), # static namespace access
C('->', Id.Expr_RArrow), # dynamic dict access: be d->name->age
# instead of d['name']['age']
C('$', Id.Expr_Dollar), # legacy regex end: /d+ $/ (better written /d+ >/
# Reserved this. Go uses it for channels, etc.
# I guess it conflicts with -4<-3, but that's OK -- spaces suffices.
C('<-', Id.Expr_Reserved),
C('=>', Id.Expr_RDArrow), # for df => filter(age > 10)
# and match (x) { 1 => "one" }
# note: other languages use |>
# R/dplyr uses %>%
C('...', Id.Expr_Ellipsis), # f(...args) and maybe a[:, ...]
C('//', Id.Expr_Reserved),
# For multiline regex literals?
C('///', Id.Expr_Reserved),
# Splat operators
C('@', Id.Expr_At),
# NOTE: Unused
C('@@', Id.Expr_DoubleAt),
] + _EXPR_NEWLINE_COMMENT + _EXPR_ARITH_SHARED