contrib: Add LPEG lexer for the zkas language.

contrib/zk.lua

@@ -0,0 +1,54 @@
+-- LPEG lexer for the zkas zk language
+local l = require('lexer')
+local token, word_match = l.token, l.word_match
+local P, R, S = lpeg.P, lpeg.R, lpeg.S
+
+local M = {_NAME = 'zk'}
+
+-- Whitespace.
+local ws = token(l.WHITESPACE, l.space^1)
+
+-- Comments.
+local comment = token(l.COMMENT, '#' * l.nonnewline_esc^0)
+
+-- Strings.
+local dq_str = P('U')^-1 * l.delimited_range('"', true)
+local string = token(l.STRING, dq_str)
+
+-- Keywords.
+local keyword = token(l.KEYWORD, word_match{
+  'constant', 'contract', 'circuit',
+})
+
+-- Types.
+local type = token(l.TYPE, word_match{
+  'EcPoint', 'EcFixedPoint', 'Base', 'BaseArray',
+  'Scalar', 'ScalarArray', 'MerklePath',
+})
+
+-- Instructions.
+local instruction = token('instruction', word_match{
+  'ec_add', 'ec_mul', 'ec_mul_base', 'ec_mul_short',
+  'ec_get_x', 'ec_get_y',
+  'poseidon_hash', 'calculate_merkle_root',
+  'constrain_instance',
+})
+
+-- Identifiers.
+local identifier = token(l.IDENTIFIER, l.word)
+
+-- Operators.
+local operator = token(l.OPERATOR, S('(){}=;,'))
+
+M._rules = {
+  {'whitespace', ws},
+  {'comment', comment},
+  {'string', string},
+  {'keyword', keyword},
+  {'type', type},
+  {'instruction', instruction},
+  {'identifier', identifier},
+  {'operator', operator},
+}
+
+return M