Strings

This chapter will discuss the three basic string-ish types. It is meaningful to group these three types together because they share data in memory. The string "true" and the message true: each share the same four bytes of memory in the heap: [ 't', 'r', 'u', 'e' ]. The values differentiate their type by tagging themeselves slightly differently - but this is an implementation detail. The important note to take from this is that converting these types into each other (eg: 'true'.messages\into) is a constant-time operation. There is no copying, nor memory allocation.

Strings

Strings are sequences of UTF8-encoded bytes. Single-quoted strings support some escape sequences, while double-quoted strings do not.

"Hello!"
'\tHello\n'
'Hello \u[2502]'

The gab\string type respects its UTF-8 Encoding. Operations that would be constant time fora gab\binary may actually be linear time for a gab\string. For example, slicing a UTF-8 string at a given index requires processing the string linearly. This is because UTF8 is a multi-byte character encoding and codepoints may be anywhere from one to four bytes long.

On the other hand, the gab\binary type is trivially convertible from gab\string, and respects bytes directly, without enforcing or respecting any encoding. Becaues of this, converting from a gab\binary to a gab\string can fail if the binary is not valid UTF-8.

smiley = '😀'

smiley.len
# => 1

smiley_bin = smiley.to\b
# => <gab\binary ...>

smiley_bin.len
# => 4

There is no syntax for string interpolation, but it is easy to construct strings out of other values using make: or sprintf:.

full_name = Strings.make("Ada" " " last_name)

'Format a value: $'.sprintf({ name: 'bob' })
# => 'Format a value: { name: bob }'

Binaries

As mentioned above, the gab\binary operates on bytes directly - there is no encoding enforced. This means indexing/slicing operations are constant-time. There is no syntax for constructing binary literals, but other types can be converted into binaries.

# Requires linearly scanning from the front of the string
"This is a string".slice(3 8)

# slices from the 3rd to 8th byte in constant time
"This will be a binary".to\b.slice(3 8)