Documentation contents

This page provides an overview of Ponscripter itself and the overall structure of a game.

The other sections are:

ponscr(6)

ponscr-syntax(7)

ponscr-ext(7)

NScripter implementations

Ogapee's ONScripter is the most significant of the clones. It supports a wide range of platforms, including handheld devices. When the attention of the English-speaking fan translation community turned to NScripter games, ONScripter was the interpreter we chose to adapt to better support the English language. The official ONScripter source code can be compiled with basic English support; since ONScripter development is aimed more at supporting new Japanese games and new platforms than at supporting localisation, the English-speaking community also maintains a branch called ONScripter-En which has a number of improvements of interest to us, including better English support as standard.

Ponscripter is a fork of ONScripter-En that drops any attempt to remain in synch with the upstream source code, and instead concentrates on providing the best possible support for Western languages. It is no longer fully NScripter-compatible, but remains an easy target to port NScripter games to when localising them.

The main enhancements are support for Unicode and for formatted text, including multiple fonts and styles, with proportional spacing, kerning, ligatures, arbitrary text size and position, etc.

Basic game structure

Unlike other NScripter-derived interpreters, which attempt to a greater or lesser degree to support Japanese filenames, Ponscripter requires that all files have plain ASCII names. It's the only way to be portable.

Script files

Script formats are distinguished by filename. The following filenames are sought, in this order:

0.utf

0.txt

nscr_sec.dat

nscript.___

pscript.dat

nscript.dat

Script structure

In reality these are parsing modes, rather than lexical sections, and control flow can be mixed up with unscrupulous use of goto and skip commands, but best practice is to keep concerns strictly separate.

A skeleton script has the following form:

; directives
*define
; define section
game
*start
; game section
end

The Directives section

The first directive line begins with a semicolon and contains one or more comma-separated tags:

mode NUM

value NUM

-*- anything -*-

The second directive line, if present, has the form

;gameid text

This is used to specify the name of the game. The gameid thus defined is used when automatically selecting a path for saved games and other variable data (see --save in ponscr(6)).

Ideally you should always specify a gameid with this directive. If you don't, Ponscripter tries to determine the name of the game by looking for a caption or versionstr command; if that also fails, a semi-unique identifier is generated based on the length of the script.

A complete directives section might thus have the form

;mode800,value500,-*- ponscripter -*-
;gameid My Ponscripter game

which would specify a game called “My Ponscripter game” that used an 800x600 display, treated all variables indexed 500 and above as globals, and would be easily identified as a Ponscripter script.

The Define section

It is introduced with the label *define, and continues until a game command is encountered.

Code in this section is evaluated non-interactively at startup, and then only touched again if the definereset command is used. It contains definitions of things like aliases, arrays, windows, subroutines, and fonts. Most of the commands valid in this section are invalid in game code, and vice versa.

The Game section

It is introduced with the game command, which transfers control immediately to the *start label (which must exist, and is normally the next thing in the script).

Processing then remains in game mode until an end command, which terminates the program, or a definereset command, which returns processing to define mode at the *define label.