String constants
Strings are enclosed by double quotes ".
Simple Strings
A plain string declared with double quotes such as "some string"
can be assigned to fields of type string:
Internally, such plain string is an instance of the standard library
feature conststring, which inherits from string. However, its
static type is string, so it cannot be assigned to a field of
type conststring:
Escaped Charactters
A plain string must not contain any of the
characters $, {, }, ", ',
or \. To include one of these characters, it must be escaped by
putting a backslash \ in front of it.
Also, a plain string must not contain any ASCII control characters in the
range of 0x00..0x1f nor the DEL character
(0x7f). In particular, a new line within a plain string is an
error.
To include any of these fobidden characters or certain ASCII control
characters, an escape sequence using a backslach \ can be used:
| Escape sequence | character | ASCII code |
|---|---|---|
\b | BS | 0x08 |
\t | HT | 0x09 |
\n | LF | 0x0a |
\f | FF | 0x0c |
\r | CR | 0x0d |
\" | " | 0x22 |
\$ | $ | 0x24 |
\' | ' | 0x27 |
\\ | \ | 0x5c |
\{ | { | 0x7b |
\} | } | 0x7d |
Here is a small example using escaped control and special characters:
Converting instances to strings
All Fuzion features are heirs of Object, which provides a
feature asString to create an instance of string from
any Fuzion instance. Any feature may redefine asString to create a
string represantation appropriate for the specific feature.
The operator prefix $ is defined as a synonyme
for asString, so a call $v is shorthand
for v.asString:
Embedded Expressions
String can be concatenated with the string representation of any instance
using infix +:
Single identifiers or numeric literals can be embedded into a string literal
using a $ immediately before the identifier as follows.
This embedding using $ does not work for expressions that consit
of more than a single identifier. For more complex expressions, you can use
curly braces { and }:
This works even for more complex code that extends over several lines:
And it is even possible to use strings with nesting in an expression nested in a string:
Multi-line Strings
There is currently no specific support for multi line strings. Concatenation of several single line strings can help as a workaround. Note that the overall string has to be wrapped in parentheses since the expression would otherwise be limited to one line.