Text Placeholder API Expressions

Adds math, conditional, and string manipulation expressions to Text Placeholder API.
This project uses Keval for parsing math expressions, and would have been exponentially more difficult without it. Show the author some love and star his repo!

Using Placeholders In Expressions

This extension uses the ${category:placeholder} syntax to allow supplying placeholders that resolve to numbers as components.
For example; to display a player's health as a percentage (such as within the tab list), you could use the following:
%expr:math ${player:health} * 100 / ${player:max_health}%%

Math Placeholder

The bulk of the additions (no pun intended) in this extension are accessed through the expr:math placeholder.

You can think of this placeholder as handling three distinct 'types':

• Components, such as numbers, functions, constants, and placeholders that resolve to numbers.
• Binary operators, such as addition or subtraction, which go between two components.
• Unary operators, such as negation and factorial, which apply to a single component.

Components and operators supplied by this extension

Binary operators are applied between two components.

Unary operators are applied to a single component.

Functions are components, taking expressions as arguments.

Constants are components which resolve to a constant value.

Conditional Placeholders

Arguments to these placeholders must be separated by semicolons (;) instead of spaces.

%expr:ifeq%

Test whether a and b are equal, and return c or d depending on the result.

%expr:ifeq aIsMath a bIsMath b cIsMath c dIsMath d%

Example

Player %expr:ifeq false; ${player:equipment_slot mainhand}; false; Diamond Sword; false; is; false; is not% holding a Diamond Sword.

%expr:iflt%

Test whether a is less than b, and return c or d depending on the result.

%expr:iflt a b cIsMath c dIsMath d%

Example

Player is in %expr:iflt ${player:health}; 14; false; poor; false; good% health

%expr:ifgt%

Test whether a is greater than b, and return c or d depending on the result.

%expr:ifgt a b cIsMath c dIsMath d%

Example

Health: %expr:ifgt ${player:health}; 4; true; ${player:health} * 100 / ${player:max_health}%; false; Nearly dead!%

String Placeholders

Arguments to these placeholders must be separated by semicolons (;) instead of spaces.

%expr:pad%, %expr:padleft%, and %expr:padright%

Pad one or both sides of str with c until the string length reaches length.

%expr:pad length; str; c% %expr:padleft length; str; c% %expr:padright length; str; c%

Example

%expr:padleft 2 ${server:online} 0% / %server:max_players%

%expr:padmatch%, %expr:padmatchleft%, and %expr:padmatchright%

Pad one or both sides of str with c until the string length matches the length of match.

%expr:padmatch match; str; c% %expr:padmatchleft match; str; c% %expr:padmatchright match; str; c%

Example

%expr:padmatchleft ${server:max_players} ${server:online} 0% / %server:max_players%