github.com/talon-one/talang/lexer is a parser

[ghost]

The package github.com/talon-one/lexer is a parser, and there is parsing related code in github.com/talon-one/token. I think that clarifying the grammar and making a single package for parsing would be beneficial. So far I think the grammar is something like:

expression = callBody | parCall | value.
parCall = "(" callBody ")".
callBody = word {arg}.
arg = word | value | parCall.
value = string | decimal | time | boolean.

With word, string, decimal, time and boolean being terminal symbols.

Also https://github.com/talon-one/talang/tree/master/docs suggests that "Mon Jan 2 15:04:05 MST 2006" is a valid time, while

talang/token/token.go

Line 253 in 8d2c20d

b.Time, err = time.Parse(time.RFC3339, text)

assumes that the correct format is time.RFC3339. I think the assumption is right since the former format has spaces and that makes it harder to parse in this context, but the documentation is confusing.