diff options
Diffstat (limited to 'doc/syntax/literals.rdoc')
| -rw-r--r-- | doc/syntax/literals.rdoc | 99 |
1 files changed, 53 insertions, 46 deletions
diff --git a/doc/syntax/literals.rdoc b/doc/syntax/literals.rdoc index ce398dd75d..c876558d4e 100644 --- a/doc/syntax/literals.rdoc +++ b/doc/syntax/literals.rdoc @@ -3,7 +3,7 @@ Literals create objects you can use in your program. Literals include: * {Boolean and Nil Literals}[#label-Boolean+and+Nil+Literals] -* {Number Literals}[#label-Number+Literals] +* {Numeric Literals}[#label-Numeric+Literals] * {Integer Literals}[#label-Integer+Literals] * {Float Literals}[#label-Float+Literals] @@ -36,7 +36,7 @@ Literals create objects you can use in your program. Literals include: +true+ is a true value. All objects except +nil+ and +false+ evaluate to a true value in conditional expressions. -== Number Literals +== \Numeric Literals === \Integer Literals @@ -136,47 +136,7 @@ Also \Rational numbers may be imaginary numbers. 12.3ir #=> Syntax error -== Strings - -=== Escape Sequences - -Some characters can be represented as escape sequences in -double-quoted strings, -character literals, -here document literals (non-quoted, double-quoted, and with backticks), -double-quoted symbols, -double-quoted symbol keys in Hash literals, -Regexp literals, and -several percent literals (<tt>%</tt>, <tt>%Q,</tt> <tt>%W</tt>, <tt>%I</tt>, <tt>%r</tt>, <tt>%x</tt>). - -They allow escape sequences 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) - \<newline> continuation line (empty string) - -The last one, <tt>\<newline></tt>, represents an empty string instead of a character. -It is used to fold a line in a string. +== \String Literals === Double-Quoted \String Literals @@ -244,7 +204,7 @@ Any combination of adjacent single-quote, double-quote, percent strings will be concatenated as long as a percent-string is not last. %q{a} 'b' "c" #=> "abc" - "a" 'b' %q{c} #=> NameError: uninitialized constant q + "a" 'b' %q{c} #=> NoMethodError: undefined method 'q' for main === Character Literal @@ -265,6 +225,46 @@ that corresponds to a single codepoint in the script encoding: ?\C-\M-a #=> "\x81", same as above ?あ #=> "あ" +=== Escape Sequences + +Some characters can be represented as escape sequences in +double-quoted strings, +character literals, +here document literals (non-quoted, double-quoted, and with backticks), +double-quoted symbols, +double-quoted symbol keys in Hash literals, +Regexp literals, and +several percent literals (<tt>%</tt>, <tt>%Q</tt>, <tt>%W</tt>, <tt>%I</tt>, <tt>%r</tt>, <tt>%x</tt>). + +They allow escape sequences 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) + \<newline> continuation line (empty string) + +The last one, <tt>\<newline></tt>, represents an empty string instead of a character. +It is used to fold a line in a string. + === Here Document Literals If you are writing a large block of text you may use a "here document" or @@ -513,7 +513,7 @@ The created string is the same as if you created it with single quotes: %q{foo{bar}baz} # => "foo{bar}baz" # braces can be nested. %q<foo<bar>baz> # => "foo<bar>baz" # angle brackets can be nested. -This is similar to single-quoted string but only backslashs and +This is similar to single-quoted string but only backslashes and the specified delimiters can be escaped with a backslash. === <tt>% and %Q</tt>: Interpolable String Literals @@ -547,6 +547,13 @@ with <tt>%w</tt> (non-interpolable) or <tt>%W</tt> (interpolable): # (not nested array). %w[foo[bar baz]qux] # => ["foo[bar", "baz]qux"] +The interpolated string is treated as a single word even if it contains +whitespace. + + s = "bar baz" + %W[foo #{s} zot] #=> ["foo", "bar baz", "zot"] + %W[foo #{"bar baz zot"} qux] # => ["foo", "bar baz zot", "qux"] + The following characters are considered as white spaces to separate words: * space, ASCII 20h (SPC) @@ -590,7 +597,7 @@ You can write a symbol with <tt>%s</tt>: This is non-interpolable. No interpolation allowed. -Only backslashs and the specified delimiters can be escaped with a backslash. +Only backslashes and the specified delimiters can be escaped with a backslash. === <tt>%r</tt>: Regexp Literals |