QUOTE(2)QUOTE(2)NAME
quotestrdup, quoterunestrdup, unquotestrdup, unquoterunestrdup,
quotestrfmt, quoterunestrfmt, quotefmtinstall, doquote, needsrcquote -
quoted character strings
SYNOPSIS
#include <u.h>
#include <libc.h>
char *quotestrdup(char *s)
Rune *quoterunestrdup(Rune *s)
char *unquotestrdup(char *s)
Rune *unquoterunestrdup(Rune *s)
int quotestrfmt(Fmt*)
int quoterunestrfmt(Fmt*)
void quotefmtinstall(void)
int (*doquote)(int c)
int needsrcquote(int c)
DESCRIPTION
These routines manipulate character strings, either adding or removing
quotes as necessary. In the quoted form, the strings are in the style
of rc(1), with single quotes surrounding the string. Embedded single
quotes are indicated by a doubled single quote. For instance,
Don't worry!
when quoted becomes
'Don''t worry!'
The empty string is represented by two quotes, ''.
The first four functions act as variants of strdup (see strcat(2)).
Each returns a freshly allocated copy of the string, created using mal‐
loc(2). Quotestrdup returns a quoted copy of s, while unquotestrdup
returns a copy of s with the quotes evaluated. The rune versions of
these functions do the same for strings (see runestrcat(2)).
The string returned by quotestrdup or quoterunestrdup has the following
properties:
1. If the original string s is empty, the returned string is ''.
2. If s contains no quotes, blanks, or control characters, the
returned string is identical to s.
3. If s needs quotes to be added, the first character of the
returned string will be a quote. For example, hello world
becomes 'hello world' not hello' 'world.
The function pointer doquote is nil by default. If it is non-nil,
characters are passed to that function to see if they should be quoted.
This mechanism allows programs to specify that characters other than
blanks, control characters, or quotes be quoted. Regardless of the
return value of *doquote, blanks, control characters, and quotes are
always quoted. Needsrcquote is provided as a doquote function that
flags any character special to rc(1).
Quotestrfmt and quoterunestrfmt are print(2) formatting routines that
produce quoted strings as output. They may be installed by hand, but
quotefmtinstall installs them under the standard format characters q
and Q. (They are not installed automatically.) If the format string
includes the alternate format character #, for example %#q, the printed
string will always be quoted; otherwise quotes will only be provided if
necessary to avoid ambiguity. In <libc.h> there are #pragma statements
so the compiler can type-check uses of %q and %Q in print(2) format
strings.
SOURCE
/sys/src/libc/port/quote.c
/sys/src/libc/fmt/fmtquote.c
SEE ALSOrc(1), malloc(2), print(2), strcat(2)QUOTE(2)
