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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/syntax/literals.rdoc | 46 |
1 files changed, 44 insertions, 2 deletions
diff --git a/doc/syntax/literals.rdoc b/doc/syntax/literals.rdoc index 194945abbd..aadd574a97 100644 --- a/doc/syntax/literals.rdoc +++ b/doc/syntax/literals.rdoc @@ -83,8 +83,33 @@ Any internal <tt>"</tt> must be escaped: "This string has a quote: \". As you can see, it is escaped" -Double-quote strings allow escaped characters such as <tt>\n</tt> for newline, -<tt>\t</tt> for tab, etc. +Double-quote strings allow escaped characters such as <tt>\n</tt> for +newline, <tt>\t</tt> for tab, etc. The full list of supported escape +sequences are as follows: + + \a bell, ASCII 07h (BEL) + \b backspace, ASCII 08h (BS) + \t horizontal tab, ASCII 09h (TAB) + \n newline (line feed), ASCII 0Ah (LF) + \v vertical tab, ASCII 0Bh (VT) + \f form feed, ASCII 0Ch (FF) + \r carriage return, ASCII 0Dh (CR) + \e escape, ASCII 1Bh (ESC) + \s space, ASCII 20h (SPC) + \\ backslash, \ + \nnn octal bit pattern, where nnn is 1-3 octal digits ([0-7]) + \xnn hexadecimal bit pattern, where nn is 1-2 hexadecimal digits ([0-9a-fA-F]) + \unnnn Unicode character, where nnnn is exactly 4 hexadecimal digits ([0-9a-fA-F]) + \u{nnnn ...} Unicode character(s), where each nnnn is 1-6 hexadecimal digits ([0-9a-fA-F]) + \cx or \C-x control character, where x is an ASCII printable character + \M-x meta character, where x is an ASCII printable character + \M-\C-x meta control character, where x is an ASCII printable character + \M-\cx same as above + \c\M-x same as above + \c? or \C-? delete, ASCII 7Fh (DEL) + +Any other character following a backslash is interpreted as the +character itself. Double-quote strings allow interpolation of other values using <tt>#{...}</tt>: @@ -124,6 +149,23 @@ be concatenated as long as a percent-string is not last. %q{a} 'b' "c" #=> "abc" "a" 'b' %q{c} #=> NameError: uninitialized constant q +One more way of writing strings is using <tt>?</tt>: + + ?a #=> "a" + +Basically only one character can be placed after <tt>?</tt>: + + ?abc #=> SyntaxError + +Exceptionally, <tt>\C-</tt>, <tt>\M-</tt> and their combination are allowed +before a character. They mean "control", "meta" and "control-meta" +respectively: + + ?\C-a #=> "\x01" + ?\M-a #=> "\xE1" + ?\M-\C-a #=> "\x81" + ?\C-\M-a #=> "\x81", same as above + === Here Documents If you are writing a large block of text you may use a "here document" or |