97 lines
3.6 KiB
Lua
Executable File
97 lines
3.6 KiB
Lua
Executable File
-- Copyright 2015-2019 Alejandro Baez (https://keybase.io/baez). See License.txt.
|
|
-- Rust LPeg lexer.
|
|
|
|
local lexer = require("lexer")
|
|
local token, word_match = lexer.token, lexer.word_match
|
|
local B, P, R, S, V = lpeg.B, lpeg.P, lpeg.R, lpeg.S, lpeg.V
|
|
local C, Cmt = lpeg.C, lpeg.Cmt
|
|
|
|
local lex = lexer.new('rust')
|
|
|
|
-- Whitespace.
|
|
lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
|
|
|
|
-- Keywords.
|
|
-- https://github.com/rust-lang/rust/blob/stable/src/libsyntax_pos/symbol.rs
|
|
lex:add_rule('keyword', token(lexer.KEYWORD, B(-P('r#')) * word_match[[
|
|
Self abstract as async auto await become box break catch const continue crate
|
|
default do dyn else enum extern false final fn for if impl in let loop macro
|
|
match mod move mut override priv pub ref return self static struct super
|
|
trait true try type typeof union unsafe unsized use virtual where while yield
|
|
]]))
|
|
|
|
-- Macro names.
|
|
lex:add_rule('macro', token(lexer.FUNCTION, lexer.word * S("!")))
|
|
|
|
-- Library types
|
|
lex:add_rule('library', token(lexer.LABEL, lexer.upper *
|
|
(lexer.lower + lexer.dec_num)^1))
|
|
|
|
-- Numbers.
|
|
local identifier = P('r#')^-1 * lexer.word
|
|
local digit = lexer.digit
|
|
local decimal_literal = digit * (digit + '_')^0
|
|
local function integer_suffix(digit)
|
|
return P('_')^0 * digit * (digit + '_')^0
|
|
end
|
|
local function opt_cap(patt)
|
|
return C(patt^-1)
|
|
end
|
|
local float = decimal_literal *
|
|
(Cmt(opt_cap('.' * decimal_literal) *
|
|
opt_cap(S('eE') * S('+-')^-1 * integer_suffix(digit)) *
|
|
opt_cap(P('f32') + 'f64'),
|
|
function (input, index, decimals, exponent, type)
|
|
return decimals ~= "" or exponent ~= "" or type ~= ""
|
|
end) +
|
|
'.' * -(S('._') + identifier))
|
|
local function prefixed_integer(prefix, digit)
|
|
return P(prefix) * integer_suffix(digit)
|
|
end
|
|
local integer = (prefixed_integer('0b', S('01')) +
|
|
prefixed_integer('0o', R('07')) +
|
|
prefixed_integer('0x', lexer.xdigit) +
|
|
decimal_literal) *
|
|
(S('iu') * (P('8') + '16' + '32' + '64' + '128' + 'size'))^-1
|
|
lex:add_rule('number', token(lexer.NUMBER, float + integer))
|
|
|
|
-- Types.
|
|
lex:add_rule('type', token(lexer.TYPE, word_match[[
|
|
() bool isize usize char str u8 u16 u32 u64 u128 i8 i16 i32 i64 i128 f32 f64
|
|
]]))
|
|
|
|
-- Strings.
|
|
local sq_str = P('b')^-1 * lexer.delimited_range("'", true)
|
|
local dq_str = P('b')^-1 * lexer.delimited_range('"')
|
|
local raw_str = Cmt(P('b')^-1 * P('r') * C(P('#')^0) * '"',
|
|
function(input, index, hashes)
|
|
local _, e = input:find('"'..hashes, index, true)
|
|
return (e or #input) + 1
|
|
end)
|
|
lex:add_rule('string', token(lexer.STRING, sq_str + dq_str + raw_str))
|
|
|
|
-- Identifiers.
|
|
lex:add_rule('identifier', token(lexer.IDENTIFIER, identifier))
|
|
|
|
-- Comments.
|
|
local line_comment = '//' * lexer.nonnewline_esc^0
|
|
local block_comment = lexer.nested_pair('/*', '*/')
|
|
lex:add_rule('comment', token(lexer.COMMENT, line_comment + block_comment))
|
|
|
|
-- Operators.
|
|
lex:add_rule('operator', token(lexer.OPERATOR,
|
|
S('+-/*%<>!=`^~@&|?#~:;,.()[]{}')))
|
|
|
|
-- Attributes.
|
|
lex:add_rule('preprocessor', token(lexer.PREPROCESSOR,
|
|
"#[" * (lexer.nonnewline - ']')^0 *
|
|
P("]")^-1))
|
|
|
|
-- Fold points.
|
|
lex:add_fold_point(lexer.COMMENT, '/*', '*/')
|
|
lex:add_fold_point(lexer.COMMENT, '//', lexer.fold_line_comments('//'))
|
|
lex:add_fold_point(lexer.OPERATOR, '(', ')')
|
|
lex:add_fold_point(lexer.OPERATOR, '{', '}')
|
|
|
|
return lex
|