-- Copyright 2006-2017 Mitchell mitchell.att.foicica.com. See LICENSE.
-- VisualBasic LPeg lexer.
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 = 'vbscript'}

-- Whitespace.
local ws = token(l.WHITESPACE, l.space ^ 1)

-- Comments.
local comment = token(l.COMMENT, (P("'") + word_match({'rem'}, nil, true)) *
                          l.nonnewline ^ 0)

-- Strings.
local string = token(l.STRING, l.delimited_range('"', true, true))

-- Numbers.
local number = token(l.NUMBER, (l.float + l.integer) * S('LlUuFf') ^ -2)

-- Keywords.
local keyword = token(l.KEYWORD, word_match({
    -- Control.
    'If', 'Then', 'Else', 'ElseIf', 'While', 'Wend', 'For', 'To', 'Each', 'In',
    'Step', 'Case', 'Select', 'Return', 'Continue', 'Do', 'Until', 'Loop',
    'Next', 'With', 'Exit', -- Operators.
    'Mod', 'And', 'Not', 'Or', 'Xor', 'Is', -- Storage types.
    'Call', 'Class', 'Const', 'Dim', 'ReDim', 'Preserve', 'Function', 'Sub',
    'Property', 'End', 'Set', 'Let', 'Get', 'New', 'Randomize', 'Option',
    'Explicit', 'On', 'Error', 'Execute', -- Storage modifiers.
    'Private', 'Public', 'Default', -- Constants.
    'Empty', 'False', 'Nothing', 'Null', 'True'
}, nil, true))

-- Types.
local type = token(l.TYPE, word_match({
    'Boolean', 'Byte', 'Char', 'Date', 'Decimal', 'Double', 'Long', 'Object',
    'Short', 'Single', 'String'
}, nil, true))

-- Identifiers.
local identifier = token(l.IDENTIFIER, l.word)

-- Operators.
local operator = token(l.OPERATOR, S('=><+-*^&:.,_()'))

M._rules = {
    {'whitespace', ws}, {'keyword', keyword}, {'type', type},
    {'comment', comment}, {'identifier', identifier}, {'string', string},
    {'number', number}, {'operator', operator}
}

return M
