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diff --git a/miralib/manual/11 b/miralib/manual/11 new file mode 100644 index 0000000..5830c60 --- /dev/null +++ b/miralib/manual/11 @@ -0,0 +1,86 @@ +_L_i_t_e_r_a_l_s + +Miranda has three types of literal constant - numerals, character +constants and string constants. + +Numerals are written in the following style + 12 5237563 24.6 4.5e13 0.63e-6 +A numeral containing decimal point and/or scale factor (`.' or `e') is +held internally as double precision (=64 bit) floating point, accuracy +approximately 17 significant figures. Integers are held in a different +internal representation, and have unbounded precision. + +The two kinds of number, integer and floating point, are both of type +`num', as far as the type-checker is concerned, and can be freely mixed +in calculations. There is automatic conversion from integer to float +when required, but not in the opposite direction. To convert from +floating point to integer, use `entier' (see standard environment). + +Negative numbers are denoted by applying the prefix `-' operator to a +numeral, thus: + -12 -4.5e13 +but note that the notation -12 is an expression, not a literal, so if +you wish to apply a function to it, you must write f (-12), not f -12, +which would be read as an attempt to subtract 12 from f. + +Integers can be written in hexadecimal (base 16) or octal (base 8) +notation starting with 0x or 0o, e.g. 4095 can also be written as 0xfff +or 0o7777. Floating point numbers can be expressed in hexadecimal +notation, optionally scaled by `p' followed by a power of 2. For +example 0x1.0p-2 means 0.25. + +Character constants are written using single quotes, thus + 'a' '0' '\n' +The type `char' includes all Unicode* characters, those outside ascii +and Latin-1 can be expressed by numeric escape codes, see below. + +Note that the functions code::char->num, decode::num->char convert +characters to and from their numeric codes. + +String constants are written using double quotes, thus + "hello dolly" "" "\n\n\n" + +Escape conventions in character and string constants are as in `C', +using the backslash character. + \' single quote + \" double quote + \\ the \ character itself + \a alarm + \b backspace + \f formfeed + \n newline + \r carriage return + \t tab + \v vertical tab +plus these numeric escapes which specify characters by code number. + \ddd up to 3 decimal digits [0-9] + \xffff up to 4 hex digits [0-9a-f] + \Xffffff up to 6 hex digits + +For escape codes to \999 you can use either decimal or hex, for example +the DELETE character can be written as \127 or \x7f. The \x and \X +forms cover the whole range of Unicode values. For example '\x3b3' is +the Greek letter lower case gamma and '\x20ac' is the euro sign. The \X +form is unlikely to be needed but is provided for completeness. + +Specifying a character by numeric code in a string or char constant has +the same effect as including it literally, so for example "£" and +"\163" are exactly the same string. + +Where a numeric escape code in a string is followed by a literal digit +(or hex digit for \x \X) the numeral can be padded with leading 0s to +force the correct parse. For example "\0078" is the alarm character \7 +followed by a literal '8', while "\78" is "N". + +Literal newlines are allowed inside string quotes if escaped by a +preceding backslash, in which case the newline is ignored (as in C). +Thus the string "hello dolly" can equally be written + "hello \ +dolly" + +A literal newline is not allowed inside character quotes. + +[* Unicode is an international standard providing numeric codes for the + symbols of practically all known human writing systems. Unicode + points 0-127 coincide with ascii and 128-255 with Latin-1.] + |