Values and strings

Variables, numbers, strings, interpolation and operators.

Variables

You create a variable by assigning to it. There is no declaration keyword, and a variable can hold any type.

name = "Ada";
age = 36;
isAdmin = true;

println( name );
println( age + 1 );
println( isAdmin );

Output:

Ada
37
true

Strings and interpolation

Put #expression# inside a double-quoted string to insert a value. The expression can be any code. Use & to join strings.

name = "Ada";
age = 36;

println( "#name# is #age# years old" );
println( "Next year: #age + 1#" );
println( "Hello, " & name & "!" );

Output:

Ada is 36 years old
Next year: 37
Hello, Ada!

To print a literal #, double it: "Issue ##42" prints Issue #42.

String functions

Most string functions work both ways: ucase( text ) or text.ucase().

title = "  MatchBox  ";

println( title.trim() );
println( title.trim().ucase() );
println( title.trim().lcase() );
println( title.trim().len() );
println( title.trim().left( 5 ) );
println( title.trim().reverse() );
println( "hello world".replace( "world", "MatchBox" ) );
println( ucFirst( "hello" ) );

Output:

MatchBox
MATCHBOX
matchbox
8
Match
xoBhctaM
hello MatchBox
Hello

Numbers and operators

println( 10 / 4 );
println( 10 \ 4 );
println( 10 % 4 );
println( 2 ^ 10 );
println( 3 > 2 );
println( true && !false );
println( 3 > 2 ? "yes" : "no" );
println( "5" + 5 );

Output:

2.5
2
2
1024
true
true
yes
10

/ is normal division, \ divides and drops the remainder, % is the remainder and ^ is a power. Notice that "5" + 5 is 10: BoxLang converts a numeric string to a number for arithmetic, while & always joins text.

Missing values

null means "no value". The elvis operator ?: supplies a default when the left side is null.

nickname = null;

println( nickname ?: "no nickname" );
println( isNull( nickname ) );

Output:

no nickname
true

Try it

Make nickname a string and run the sample again. Then write a line that prints your name in capitals, followed by its length.