1 files changed, 119 insertions, 0 deletions
diff --git a/lua/lexers/gleam.lua b/lua/lexers/gleam.lua
new file mode 100644
index 0000000..6aee725
--- /dev/null
+++ b/lua/lexers/gleam.lua
@@ -0,0 +1,119 @@
+-- Copyright 2021-2022 Mitchell. See LICENSE.
+-- Gleam LPeg lexer
+-- https://gleam.run/
+-- Contributed by Tynan Beatty
+
+local lexer = require('lexer')
+local token, word_match = lexer.token, lexer.word_match
+local P, S = lpeg.P, lpeg.S
+
+local KEY, OP = lexer.KEYWORD, lexer.OPERATOR
+
+local lex = lexer.new('gleam')
+
+-- Whitespace.
+local gleam_ws = token(lexer.WHITESPACE, lexer.space^1)
+lex:add_rule('whitespace', gleam_ws)
+
+-- Types.
+local typ_tok = token(lexer.TYPE, lexer.upper * lexer.alnum^0)
+lex:add_rule('type', typ_tok)
+
+-- Modules.
+local name = (lexer.lower + '_') * (lexer.lower + lexer.digit + '_')^0
+local fn_name = token(lexer.FUNCTION, name)
+local mod_name = token('module', name)
+local typ_or_fn = typ_tok + fn_name
+local function mod_tok(ws)
+  return token(KEY, 'import') * ws^1 * mod_name * (ws^0 * token(OP, '/') * ws^0 * mod_name)^0 *
+    (ws^1 * token(KEY, 'as') * ws^1 * mod_name)^-1 *
+    (ws^0 * token(OP, '.') * ws^0 * token(OP, '{') * ws^0 * typ_or_fn *
+      (ws^0 * token(OP, ',') * ws^0 * typ_or_fn)^0 * ws^0 * token(OP, '}'))^-1
+end
+lex:add_rule('module', mod_tok(gleam_ws))
+lex:add_style('module', lexer.styles.constant)
+
+-- Keywords.
+local key_tok = token(KEY, word_match(
+  'as assert case const external fn if import let opaque pub todo try tuple type'))
+lex:add_rule('keyword', key_tok)
+
+-- Functions.
+local function fn_tok(ws)
+  local mod_name_op = mod_name * ws^0 * token(OP, '.')
+  local fn_def_call = mod_name_op^-1 * ws^0 * fn_name * ws^0 * #P('(')
+  local fn_pipe = token(OP, '|>') * ws^0 * (token(KEY, 'fn') + mod_name_op^-1 * fn_name)
+  return fn_def_call + fn_pipe
+end
+lex:add_rule('function', fn_tok(gleam_ws))
+
+-- Labels.
+local id = token(lexer.IDENTIFIER, name)
+local function lab_tok(ws)
+  return token(OP, S('(,')) * ws^0 * token(lexer.LABEL, name) * #(ws^1 * id)
+end
+lex:add_rule('label', lab_tok(gleam_ws))
+
+-- Identifiers.
+local discard_id = token('discard', '_' * name)
+local id_tok = discard_id + id
+lex:add_rule('identifier', id_tok)
+lex:add_style('discard', lexer.styles.comment)
+
+-- Strings.
+local str_tok = token(lexer.STRING, lexer.range('"'))
+lex:add_rule('string', str_tok)
+
+-- Comments.
+local com_tok = token(lexer.COMMENT, lexer.to_eol('//'))
+lex:add_rule('comment', com_tok)
+
+-- Numbers.
+local function can_neg(patt) return (lpeg.B(lexer.space + S('+-/*%<>=&|:,.')) * '-')^-1 * patt end
+local function can_sep(patt) return (P('_')^-1 * patt^1)^1 end
+local dec = lexer.digit * can_sep(lexer.digit)^0
+local float = dec * '.' * dec^0
+local bin = '0' * S('bB') * can_sep(S('01')) * -lexer.xdigit
+local oct = '0' * S('oO') * can_sep(lpeg.R('07'))
+local hex = '0' * S('xX') * can_sep(lexer.xdigit)
+local num_tok = token(lexer.NUMBER, can_neg(float) + bin + oct + hex + can_neg(dec))
+lex:add_rule('number', num_tok)
+
+-- Operators.
+local op_tok = token(OP, S('+-*/%#!=<>&|.,:;{}[]()'))
+lex:add_rule('operator', op_tok)
+
+-- Errors.
+local err_tok = token(lexer.ERROR, lexer.any)
+lex:add_rule('error', err_tok)
+
+-- Fold points.
+lex:add_fold_point(lexer.COMMENT, lexer.fold_consecutive_lines('//'))
+lex:add_fold_point(lexer.OPERATOR, '{', '}')
+lex:add_fold_point(lexer.OPERATOR, '[', ']')
+lex:add_fold_point(lexer.OPERATOR, '(', ')')
+
+-- Embedded Bit Strings.
+-- Mimic lexer.load() by creating a bitstring-specific whitespace style.
+local bitstring = lexer.new(lex._NAME .. '_bitstring')
+local bitstring_ws = token(bitstring._NAME .. '_whitespace', lexer.space^1)
+bitstring:add_rule('whitespace', bitstring_ws)
+bitstring:add_style(bitstring._NAME .. '_whitespace', lexer.styles.whitespace)
+bitstring:add_rule('type', typ_tok)
+bitstring:add_rule('module', mod_tok(bitstring_ws))
+bitstring:add_rule('keyword', key_tok + token(KEY, word_match{
+  'binary', 'bytes', 'int', 'float', 'bit_string', 'bits', 'utf8', 'utf16', 'utf32',
+  'utf8_codepoint', 'utf16_codepoint', 'utf32_codepoint', 'signed', 'unsigned', 'big', 'little',
+  'native', 'unit', 'size'
+}))
+bitstring:add_rule('function', fn_tok(bitstring_ws))
+bitstring:add_rule('label', lab_tok(bitstring_ws))
+bitstring:add_rule('identifier', id_tok)
+bitstring:add_rule('string', str_tok)
+bitstring:add_rule('comment', com_tok)
+bitstring:add_rule('number', num_tok)
+bitstring:add_rule('operator', op_tok)
+bitstring:add_rule('error', err_tok)
+lex:embed(bitstring, token(OP, '<<'), token(OP, '>>'))
+
+return lex