STRINGS

A string is a piece of text: a name, a sentence, a line from a file. In satellite it is satellite.variable.string, and you write its value between double quotes.

satellite keeps a string as characters, not as bytes. An accented letter, an arrow or a Japanese character is one character, so turning a string round works the way you would expect, in any language.

Joining, taking away and finding

+ joins two strings into one, and .add(x) does the same. - takes away the first place the right-hand string appears, and leaves the string unchanged when it is not there. .find(x) tells you where x first begins, counting from 0. .reverse() turns the string round.

satellite.include(satellite)

satellite.capsule satellite.main()
{
    satellite.variable.string s = "hello world"
    satellite.console.display(s + "!")
    satellite.console.display(s.add("!"))
    satellite.console.display(s - "o")
    satellite.console.display(s - "z")
    satellite.console.display(s.find("world"))
    satellite.console.display(s.reverse())
    satellite.console.display("héllo→".reverse())
    satellite.console.display("日本語".reverse())
    satellite.return(satellite)
}

hello world!
hello world!
hell world
hello world
6
dlrow olleh
→olléh
語本日

s - "o" took away only the first “o”, from “hello”, and left the one in “world”. If .find cannot find what you asked for, it does not answer -1 the way some languages do: it stops with S420, “did not find it”, so a missing piece of text never passes silently as a number.

Strings and numbers

A number added to a string joins it as its digits: "n = " + 4 is n = 4, and so is "n = " + 4.string. With the number first, text that spells a number is added — 4 + "2" is the number 6 — and any other text is joined: 4 + " apples" is 4 apples. Every other conversion you say out loud:

• a number becomes text with .string (also .to_string and .str)
• text becomes a whole number with .number (also .as_number and .to_number)
• .binary (also .bin) and .hex read the number in the text and answer its digits in base 2 or base 16, as a string

Methods chain from left to right, so "87".bin.find("111") reads 87, writes it in binary, and looks for “111” in that.

satellite.include(satellite)

satellite.capsule satellite.main()
{
    satellite.variable.number n = 4
    satellite.console.display("n = " + n.to_string())
    satellite.console.display("42".number + 1)
    satellite.console.display("42".bin)
    satellite.console.display("255".hex)
    satellite.console.display("87".bin)
    satellite.console.display("87".bin.find("111"))
    satellite.return(satellite)
}

n = 4
43
101010
FF
1010111
4

.number reads only a whole number. "3.5".number is refused (S120), because satellite does not round anything unless you ask it to.

Here is the join with nothing written out, both ways round:

satellite.include(satellite)

satellite.capsule satellite.main()
{
    satellite.variable.number n = 4
    satellite.console.display("n = " + n)
    satellite.console.display(n + " apples")
    satellite.console.display(n + "2")
    satellite.return(satellite)
}

n = 4
4 apples
6

Comparing strings

== and != ask whether two strings are the same. < and > put them in order using satellite’s own alphabet: the small letters a to z first, then the capitals A to Z, then the digits, then other signs, then the space. So "a" < "B" is true, and "Z" < "a" is false.

satellite.include(satellite)

satellite.capsule satellite.main()
{
    satellite.variable.string fruit = "apple"
    satellite.console.display(fruit == "apple")
    satellite.console.display(fruit != "pear")
    satellite.console.display("apple" < "banana")
    satellite.console.display("a" < "B")
    satellite.console.display("Z" < "a")
    satellite.return(satellite)
}

true
true
true
true
false

Good to know

• A string can carry colour: "OK".foreground(x00FF00) is the word OK in green when it is shown in a terminal. See COLOR ON THE CONSOLE.
• A backslash starts an escape: \" is a double quote, \\ a backslash, \n a new line, \t a tab, \r a carriage return and \' an apostrophe, so "tab\there" shows tab, a tab, and here. Any other backslash stays in the text as you wrote it.
• Several string methods are named in the language and not built yet, and satl refuses each one today: among them .size, .upper, .lower, .split, .replace, .trim and .substring, as well as reading one character with s[n].

Where next

The FULL REFERENCE lists every string word. For putting text on the screen, read DISPLAYING TEXT, and for turning numbers into text and back, read NUMBERS.