Library
Module
Module type
Parameter
Class
Class type
US-ASCII string support.
References.
- Vint Cerf. ASCII format for Network Interchange. RFC 20, 1969.
Predicates
is_valid s
is true
iff only for all indices i
of s
, s.[i]
is an US-ASCII character, i.e. a byte in the range [0x00
;0x7F
].
Casing transforms
The following functions act only on US-ASCII code points that is on bytes in range [0x00
;0x7F
], leaving any other byte intact. The functions can be safely used on UTF-8 encoded strings; they will of course only deal with US-ASCII casings.
uppercase s
is s
with US-ASCII characters 'a'
to 'z'
mapped to 'A'
to 'Z'
.
lowercase s
is s
with US-ASCII characters 'A'
to 'Z'
mapped to 'a'
to 'z'
.
capitalize s
is like uppercase
but performs the map only on s.[0]
.
uncapitalize s
is like lowercase
but performs the map only on s.[0]
.
Escaping to printable US-ASCII
escape s
is s
with:
- Any
'\\'
(0x5C
) escaped to the sequence"\\\\"
(0x5C
,0x5C
). - Any byte in the ranges [
0x00
;0x1F
] and [0x7F
;0xFF
] escaped by an hexadecimal"\xHH"
escape withH
a capital hexadecimal number. These bytes are the US-ASCII control characters and non US-ASCII bytes. - Any other byte is left unchanged.
unescape s
unescapes what escape
did. The letters of hex escapes can be upper, lower or mixed case, and any two letter hex escape is decoded to its corresponding byte. Any other escape not defined by escape
or truncated escape makes the function return None
.
The invariant unescape (escape s) = Some s
holds.
escape_string s
is like escape
except it escapes s
according to OCaml's lexical conventions for strings with:
- Any
'\b'
(0x08
) escaped to the sequence"\\b"
(0x5C,0x62
). - Any
'\t'
(0x09
) escaped to the sequence"\\t"
(0x5C,0x74
). - Any
'\n'
(0x0A
) escaped to the sequence"\\n"
(0x5C,0x6E
). - Any
'\r'
(0x0D
) escaped to the sequence"\\r"
(0x5C,0x72
). - Any
'\"'
(0x22
) escaped to the sequence"\\\""
(0x5C,0x22
). - Any other byte follows the rules of
escape
unescape_string
is to escape_string
what unescape
is to escape
and also additionally unescapes the sequence "\\'"
(0x5C,0x27
) to "'"
(0x27
).