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Diffstat (limited to 'system/doc/reference_manual/expressions.xml')
| -rw-r--r-- | system/doc/reference_manual/expressions.xml | 40 |
1 files changed, 23 insertions, 17 deletions
diff --git a/system/doc/reference_manual/expressions.xml b/system/doc/reference_manual/expressions.xml index 497d7eb464..d564b20ca6 100644 --- a/system/doc/reference_manual/expressions.xml +++ b/system/doc/reference_manual/expressions.xml @@ -4,7 +4,7 @@ <chapter> <header> <copyright> - <year>2003</year><year>2011</year> + <year>2003</year><year>2012</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> @@ -561,11 +561,15 @@ number < atom < reference < fun < port < pid < tuple < list <p>Lists are compared element by element. Tuples are ordered by size, two tuples with the same size are compared element by element.</p> - <p>If one of the compared terms is an integer and the other a - float, the integer is first converted into a float, unless the - operator is one of =:= and =/=. If the integer is too big to fit - in a float no conversion is done, but the order is determined by - inspecting the sign of the numbers.</p> + <p>When comparing an integer to a float, the term with the lesser + precision will be converted into the other term's type, unless the + operator is one of =:= or =/=. A float is more precise than + an integer until all significant figures of the float are to the left of + the decimal point. This happens when the float is larger/smaller than + +/-9007199254740992.0. The conversion strategy is changed + depending on the size of the float because otherwise comparison of large + floats and integers would lose their transitivity.</p> + <p>Returns the Boolean value of the expression, <c>true</c> or <c>false</c>.</p> <p>Examples:</p> @@ -681,7 +685,7 @@ Expr1 <input>op</input> Expr2</pre> 8> <input>2#10 bor 2#01.</input> 3 9> <input>a + 10.</input> -** exception error: bad argument in an arithmetic expression +** exception error: an error occurred when evaluating an arithmetic expression in operator +/2 called as a + 10 10> <input>1 bsl (1 bsl 64).</input> @@ -879,9 +883,8 @@ Ei = Value | and UTF-32, respectively.</p> <p>When constructing a segment of a <c>utf</c> type, <c>Value</c> - must be an integer in one of the ranges 0..16#D7FF, - 16#E000..16#FFFD, or 16#10000..16#10FFFF - (i.e. a valid Unicode code point). Construction + must be an integer in the range 0..16#D7FF or + 16#E000....16#10FFFF. Construction will fail with a <c>badarg</c> exception if <c>Value</c> is outside the allowed ranges. The size of the resulting binary segment depends on the type and/or <c>Value</c>. For <c>utf8</c>, @@ -896,14 +899,13 @@ Ei = Value | <c><![CDATA[<<$a/utf8,$b/utf8,$c/utf8>>]]></c>.</p> <p>A successful match of a segment of a <c>utf</c> type results - in an integer in one of the ranges 0..16#D7FF, 16#E000..16#FFFD, - or 16#10000..16#10FFFF - (i.e. a valid Unicode code point). The match will fail if returned value + in an integer in the range 0..16#D7FF or 16#E000..16#10FFFF. + The match will fail if returned value would fall outside those ranges.</p> <p>A segment of type <c>utf8</c> will match 1 to 4 bytes in the binary, if the binary at the match position contains a valid UTF-8 sequence. - (See RFC-2279 or the Unicode standard.)</p> + (See RFC-3629 or the Unicode standard.)</p> <p>A segment of type <c>utf16</c> may match 2 or 4 bytes in the binary. The match will fail if the binary at the match position does not contain @@ -991,15 +993,19 @@ fun Module:Name/Arity</pre> <pre> fun (Arg1,...,ArgN) -> Name(Arg1,...,ArgN) end</pre> <p>In <c>Module:Name/Arity</c>, <c>Module</c> and <c>Name</c> are atoms - and <c>Arity</c> is an integer. + and <c>Arity</c> is an integer. Starting from the R15 release, + <c>Module</c>, <c>Name</c>, and <c>Arity</c> may also be variables. A fun defined in this way will refer to the function <c>Name</c> - with arity <c>Arity</c> in the <em>latest</em> version of module <c>Module</c>. + with arity <c>Arity</c> in the <em>latest</em> version of module + <c>Module</c>. A fun defined in this way will not be dependent on + the code for module in which it is defined. </p> <p>When applied to a number N of arguments, a tuple <c>{Module,FunctionName}</c> is interpreted as a fun, referring to the function <c>FunctionName</c> with arity N in the module <c>Module</c>. The function must be exported. - <em>This usage is deprecated.</em> + <em>This usage is deprecated.</em> Use <c>fun Module:Name/Arity</c> + instead. See <seealso marker="#calls">Function Calls</seealso> for an example.</p> <p>More examples can be found in <em>Programming Examples</em>.</p> </section> |