[RESOLVED] [RegEx] Syntax Checker

[dday9]

For those of you who do not know, I'm trying to create my own programming language. No so much to make the next best language, but because I'm really interested in doing it. What I'm trying to do is create a syntax checker for the declaration process. Here are a little bit of details on it:

<access modifier> <identifier> as <data type>

Access Modifiers:

1. local
2. global

Data Types:

1. Boolean
2. Decimal
3. Number
4. String

So an example would be:

local fooVar as string

Look familiar? ;]

Anyways. Before I was simply using a bunch of conditional statements to check if the syntax was in the correct layout. Now I've decided to use RegEx. This is the pattern that I've tried:

\blocal|\bglobal [a-zA-Z] \bas \bboolean|\bdecimal|\bnumber|\bstring

but whenever I try my example above it only matches local and string. If I change local to global then it doesn't match. The data type matches all types except for the Boolean type. How can I fix this?

[dday9]

I was able to work it up:

^(global|local) ([^\s]+) (as) (boolean|decimal|number|string)$

Explanation:

^(global|local)	Match either the word global or the word local at the beginning of the string
([^\s]+)	Match the word before the whitespace
(as)	Match the word as
(boolean|decimal|number|string)$	Match the word: Boolean, decimal, number, or string at the end of the sentence

[dday9]

I was able to improve it a little bit:

^(global|local) ([a-zA-Z-0-9_]+) (as) (boolean|decimal|number|string)$

Explanation:

^(global|local)	Match either the word global or the word local at the beginning of the string
([a-zA-Z-0-9_]+)	Match any sequence of characters that are letters, numeric, or an underscore
(as)	Match the word as
(boolean|decimal|number|string)$	Match the word: Boolean, decimal, number, or string at the end of the sentence

[dday9]

I was able to improve it even more with the help of some people on DIC forums:

^(global|local) ([a-zA-Z_][a-zA-Z-0-9_]*) (as) (boolean|decimal|number|string)$

Explanation:

^(global|local)	Match either the word global or the word local at the beginning of the string
([a-zA-Z_][a-zA-Z-0-9_]*)	Match any sequence of characters that are letters, numeric, or an underscore that doesn't start with a character that's numeric
(as)	Match the word as
(boolean|decimal|number|string)$	Match the word: Boolean, decimal, number, or string at the end of the sentence