This program is a file parser. It is very usefull for practically every type of program. I would recommend you learning pointers and variable types before using this. What it allows you to do is load a file and then parse tags from it.
For example:
If you wanted to parse the tag <cash>, you would simply call the function parse_tag with "cash" as the first parameter and it would return the value in between <cash> and </cash> as a variable type called str_array which is just a record that contains an array of strings and the upper bound.
So now your function call looks like this:
| code: |
parse_tag ("cash", |
What if you have more than one tag in the file named "cash"? Well, the second parameter in the parse_tag function is the tag number. If you want the second "cash" then you would use 2 as the tag number. If you wanted the first, third or even tength tag you would use 1, 3 or 10. For this example we will use the first.
You function call now looks like this:
| code: |
parse_tag ("cash", 1, |
The third parameter can remain nil for now because that required some more explaining.
So you are left with:
| code: |
parse_tag ("cash", 1, nil) |
In a simple program you must first initialize the parser and load the file.
To do this you would call the procedures:
| code: |
initialize () load_file (file_name : string) |
There is one final thing to remember. The parser is a class so you need to have a pointer to it to use it.
A simple program that parses this file,
| code: |
testfile.txt <name> ericfourofur </name> <age> 16 </age> |
and displays the name and age would look like this:
| code: |
import FileParser var parser : ^FileParser := nil new FileParser, parser parser -> initialize () if not parser -> load_file ("testfile.txt") then %There was an error loading the file end if var name := parser -> parse_tag ("name", 1, nil) if name = nil then %There was an error parsing the name end if var age := parser -> parse_tag ("age", 1, nil) if age = nil then %There was an error parsing the name end if for i : 0 .. name -> bound put name -> str (i) end for for i : 0 .. age -> bound put age -> str (i) end for |
The code is over commented so it should be easy to understand. There is also a program named File Parser Test that shows all of the features of the parser and it is over commented aswell.
Edit 1: spelling mistake
Edit 2: added documentation
Edit 3: fixed a mistake in FileParser (9 characters of one line were causing me a lot of grief
)
) but I was just wondering what a "parser" was.