Elanthe at 03:18, 19 January 2025

2025-01-19T03:18:56Z

Elanthe: Created page with "=Prog Structure and Practice= "It's just a puzzle box." -- Kirstie, Hellraiser : Firstly, there are three classes of entities in the game which can have progs: Mobiles, : Objects, and Rooms. Broadly speaking, the syntax used on each of these prog types is the : same. Respectively, these are referred to as mobprogs, objprogs, or room progs. Over time, : the prog system has been rationalized so that the syntax for mpcommands and if checks is : the same acros..."

2025-01-19T03:07:03Z

Created page with "=Prog Structure and Practice= "It's just a puzzle box." -- Kirstie, Hellraiser : Firstly, there are three classes of entities in the game which can have progs: Mobiles, : Objects, and Rooms. Broadly speaking, the syntax used on each of these prog types is the : same. Respectively, these are referred to as mobprogs, objprogs, or room progs. Over time, : the prog system has been rationalized so that the syntax for mpcommands and if checks is : the same acros..."

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=Prog Structure and Practice=

"It's just a puzzle box."
-- Kirstie, Hellraiser

: Firstly, there are three classes of entities in the game which can have progs: Mobiles,
: Objects, and Rooms. Broadly speaking, the syntax used on each of these prog types is the
: same. Respectively, these are referred to as mobprogs, objprogs, or room progs. Over time,
: the prog system has been rationalized so that the syntax for mpcommands and if checks is
: the same across the type of entity. "Mobprog" is therefore often used to refer to the general
: class of all prog types, and this is the usage which will be employed in this document. Every
: prog has the following structure:

[prog_trigger] [modifier] [argument]
Body of Prog:
{
(Control structures)
(Commands)
}

: It isn't immediately obvious by what we mean by all these terms, so let's try to clarify them:

prog_trigger
: The prog_trigger reflects a central fact about progs: All progs are, in fact, a set of actions
: which occur in response to a triggering event. What a trigger really says is, "Execute the
: commands that are in my body when conditions matching my trigger are met".

: To take a concrete example, consider the following prog_trigger:

: Greet_prog:
: Syntax: greet_prog <Percentage value from 1-100>

: A greet_prog triggers whenever a pc enters the room with the object/room/mob. The chance that
: the greet prog triggers is equal to the percentage value given as an argument.

: Ex:
: greet_prog 50
: say Hello there!

: So, this mob has a 50% chance any time a pc enters the room of triggering the prog, at which
: point the pc will see the mob saying "Hello there!"

: Another example of a prog trigger which does not have a percentage argument is the speech_prog.

: Syntax: speech_prog [p] [argument]

: Speech_prog triggers if [argument] is said aloud in the same room as mobile or object. The "p"
: determines whether or not the match must be exact or simply a substring match. If no argument is
: specified, the speech_prog will trigger on any speech at all.

: Ex:
: speech_prog p Hello
: say Hi there!

: Now, a mobile with this program would respond whenever someone said "hello" to the mob.

The Prog Body:
: The body of the prog is where the 'meat' of the prog resides. Broadly speaking, you will find
: two types of things within the body:

: Commands
: Control Structures

==(i) Commands==

: Commands are actions that the mob can perform. As a general rule, mobiles can perform any
: action a player can that does not involve the use of a skill or spell. [They can do these
: as well, but it requires a special other thing to be done first.]

: In addition to these normal commands, there are a suite of prog-specific commands. These
: commands are designed to allow progs to duplicate imm commands, player skills or spells, or to
: just generally do interesting things. To take a concrete example, consider the following prog
: specific command:

: mpgoto:
: Syntax: mpgoto <vnum>

: When executed from within a mob prog, mpgoto causes the mobile in question to goto the room
: with vnum specified. Taking the examples we've seen, we can construct a very simple prog:

: greet_prog 100
: say Oh no, people!
: mpgoto 5000

: In the above prog, "greet_prog" is the prog trigger, and the say and the mpgoto are examples
: of commands. This prog basically says, "Whenever someone enters the same room as this mob,
: have it say "Oh no, people!", then have the mob goto room 5000".

: This is a very basic prog, but might be used on a mischievous imp or forest spirit. [And a
: cunning player would go to room 5000, and ambush the imp there!] There are many, many different
: mpcommands, so we'll detail those in their own chapter.

==(ii) Control Structures==

: Normally, commands in the body of a prog are executed in linear order. I.e., if we have a prog:

: prog_trigger
: command 1
: command 2
: command 3

: When the prog triggers, it will execute command 1, then command 2, then command 3, and so on, line
: by line, from top to bottom.

: Control structures allow us to control the natural order of prog execution. Structures exist to
: allow for logical branching, multiple conditionals, looping, subroutines, and numerous other
: functions. To take a concrete example, consider the "loop" statement:

: Loop:
: Syntax: loop <lower number> to <higher number>
: [Body of loop]
: endloop

: The loop structure, like its name implies, will loop through the body of the loop, executing the
: lines within for every iteration of the loop. So, consider the following prog:

: greet_prog 100
: loop 1 to 3
: say Hey Hey!
: endloop

: This prog will trigger when someone enters the room. It will then hit the loop, so it will
: execute its contents three times. So, if I enter a room with a mob who had this prog, I will
: see:

: Mob says, 'Hey Hey!' [this is when the loop is on 1]
: Mob says, 'Hey Hey!' [this is when the loop is on 2]
: Mob says, 'Hey Hey!' [this is when the loop is on 3]

: Later, we'll give control structures their own chapter. But for right now, the important thing
: is to realize is that the default behavior for a prog is to execute its commands in order, and
: control structures exist to change the order in which commands are executed.

Avendar:Prog Section 1 - Revision history

Elanthe at 03:18, 19 January 2025