The engine can load .coa text files which are just text files with the extension changed.
You can see Example Story.coa for a brief example of the majority of what this engine provides in action.
The file is parsed from top to bottom a line at a time. If a line starts with a command token (see farther down for commands), the command is executed.
If no command token is present (or it's escaped with \ at the start), the line is just sent to the text area for the player.
The program will wait for reader interaction if it reaches a >w command (see that command for more details) or if the end of the file is reached.
Text displayed to the reader can contain a variable (more on them in the next section) name surrounded by < and > to insert a variable value in the text.
In the following example >h is the command token for a header and the rest of the line is processed differently (see farther down for that command), but the next two lines will just be sent to the text area.
>h Chapter 1: <name> Awakens...
You wake up in what appears to be an old rusty cell. Sun light filters through the tiny windows from outside the cell.
It is quiet and you don't see anyone around.
Empty lines are ignore. If you wish to put a line break in your story text just include a "\ " (backslash + space) on that, otherwise empty, line.
Variables can also affect the flow of the story. There are three main vairable types: Flags, Numbers, and Strings
Flags are simple in that they exist or don't exist. They don't store data.
Numbers can contain a number that can be operated on or compared.
Strings sadly have very limitted use. You can take input from the reader, display strings, and test equality on them.
Some commands can take expressions. These take the form of [!]<flag> or <varA><comparison><val | varB>. Do note there is no space between variables and ops.
<flag> will return true if "flag" exists.
!<flag> will return true if "flag" does NOT exist.
Comparisons:
= Equal (To test for an empty string use <var>='' (two single quotes after the equals).
! NOT equal
< Less than
[ Less than OR equal to
> Greater than
] Greater than OR equal to
Clears the text area.
Deletes all story flags and variables.
[value] is parsed to the end of the line (i.e. it can have spaces).
Creates a flag wth name <name> if [value] is not supplied.
Creates a Number if [value] contains a number.
Creates a String containing [value] if previous case is not met.
Examples:
>f tookKeys will create a flag labeled "tookKeys".
>f bullets 3 will create a number variable named "bullets" and set it to 3.
>f secret Best secret password will create a String variable named "secret" and set it to "Best secret password".
Performs <op> on <nameA> and <nameB | val>. Then stores result in <nameA>. Do note that there is no space between the names and operator.
Operators:
+ Addition
- Substraction
* Multiplication
/ Division
% Remainder
: Copy (Copies the value of <nameB | val> into <nameA>)
Examples:
>f bullets-1 will subtract 1 from variable "bullets".
>f cash+money will add variable "money" to variable "cash".
>f before:message will copy variable "message" into variable "before".
Deletes flag/variable <name>.
Examples:
>fd tookKeys would delete the "tookKeys" flag.
Sets the header text to <text>.
<text> is parsed to the end of the line (i.e. it can have spaces) and it can have variables inserted in it.
Examples:
>h Chapter 1: <name> Awakens! would set the header text to "Chapter 1: Nick Awakens!" assuming there was variable "name" that had the text "Nick" stored in it.
Displays a input text box to the reader with <prompt> displayed. The input will be stored in variable <name>.
<prompt> is parsed to the end of the line (i.e. it can have spaces) and it can have variables inserted in it.
Examples:
>i reader What is your name? Would prompt "What is your name?" and store the input in the variable "reader"
Jumps story to next label <label> or loops to start of story and checks again.
This is used in conjunction with >l (see that command) to jump to different story places.
Examples:
>j ending1 Jumps the story to label "ending1"
If <expression> is true, jumps story to next label <label> or loops to start of story and checks again.
This is used in conjunction with >l (see that command) to jump to different story places.
Examples:
>jf key unlockDoor If flag "key" exists, jumps the story to label "unlockDoor".
>jf !cutPower startMachine If flag "cutPower" does NOT exist, jumps the story to label "startMachine".
>jf timeWaited>3 tooLate If variable "timeWaited" is greater than 3, jumps the story to label "tooLate".
Defines a label to jump to.
Note: Be careful if you use "next" as a label. >j and >jf can use "next" as a valid label, but >o and >of can NOT use it because they use that keyword to continue where the engine left off.
Used in conjunction with >j, >jf, >o, and >of (see those commands) to jump to different story places.
Examples:
>l ending1 Defines label "ending1" for jumping to.
Creates a button with text <text> and that, when clicked, jumps the story to <label>. Using the next keyword just tells the engine to continue where it is.
<text> is parsed to the end of the line (i.e. it can have spaces) and it can have variables inserted in it.
Examples:
>o upLadder Climb the ladder. Creates a button with text "Climb the ladder." that jumps to label "upLadder".
>o next Insert <count> quarters. Creates a button with text "Insert 3 quarters" (assuming variable "count" is 3) that continues right where the engine last stopped.
If <expression> is true, creates a button with text <text> and that, when clicked, jumps the story to <label>. Using the next keyword just tells the engine to continue where it is.
<text> is parsed to the end of the line (i.e. it can have spaces) and it can have variables inserted in it.
Examples:
of carFueled driveAway Drive away. If flag "carFueled" exists, create button with text "Drive away." that jumps to label "driveAway".
of !cutPower next Start machine. If flag "cutPower" does NOT exist, create button with text "Start machine." that that continues right where the engine last stopped.
of snacks>0 eatSnack Eat a snack. If variable "snacks" is greater than zero, create button with text "Eat a snack." that jumps to label "eatSnack".
Chooses a random integer in range [<min>, <max>) and stores it in variable <name>.
Examples:
>r hoursSlept 2 5 will pick 2, 3, or 4 at random and store it in variable "hoursSlept".
If <expression> is true, Displays <text>.
<text> is parsed to the end of the line (i.e. it can have spaces) and it can have variables inserted in it.
Examples:
>tf sawPassword You remembered their password was "best secret" from earlier. If flag "sawPassword" exists, displays "You remembered their password was "best secret" from earlier."
>tf !tookKeys You realize you forgot your keys and go back to get them. If flag "tookKeys" does NOT exist, displays "You realize you forgot your keys and go back to get them."
>tf waits>1 You have waited <waits> times. If variable "waits" is greater than one, displays "You have waited 2 times." (assuming that waits is two).
Causes the engine to halt execution until the reader does something.
Most common use case is after a block of buttons so the reader can make a choice.
Yes I know this engine is jank AF. Too bad!