diff options
Diffstat (limited to 'erts/doc/src/match_spec.xml')
| -rw-r--r-- | erts/doc/src/match_spec.xml | 54 |
1 files changed, 50 insertions, 4 deletions
diff --git a/erts/doc/src/match_spec.xml b/erts/doc/src/match_spec.xml index b9f955e4db..f0390c9db8 100644 --- a/erts/doc/src/match_spec.xml +++ b/erts/doc/src/match_spec.xml @@ -60,7 +60,7 @@ <section> <title>Grammar</title> - <p>A match_spec can be described in this <em>informal</em> grammar:</p> + <p>A match_spec used in tracing can be described in this <em>informal</em> grammar:</p> <list type="bulleted"> <item>MatchExpression ::= [ MatchFunction, ... ] </item> @@ -117,6 +117,52 @@ <c><![CDATA[display]]></c> | <c><![CDATA[caller]]></c> | <c><![CDATA[set_tcw]]></c> | <c><![CDATA[silent]]></c></item> </list> + + <p>A match_spec used in ets can be described in this <em>informal</em> grammar:</p> + <list type="bulleted"> + <item>MatchExpression ::= [ MatchFunction, ... ] + </item> + <item>MatchFunction ::= { MatchHead, MatchConditions, MatchBody } + </item> + <item>MatchHead ::= MatchVariable | <c><![CDATA['_']]></c> | { MatchHeadPart, ... } + </item> + <item>MatchHeadPart ::= term() | MatchVariable | <c><![CDATA['_']]></c></item> + <item>MatchVariable ::= '$<number>' + </item> + <item>MatchConditions ::= [ MatchCondition, ...] | <c><![CDATA[[]]]></c></item> + <item>MatchCondition ::= { GuardFunction } | + { GuardFunction, ConditionExpression, ... } + </item> + <item>BoolFunction ::= <c><![CDATA[is_atom]]></c> | <c><![CDATA[is_constant]]></c> | + <c><![CDATA[is_float]]></c> | <c><![CDATA[is_integer]]></c> | <c><![CDATA[is_list]]></c> | + <c><![CDATA[is_number]]></c> | <c><![CDATA[is_pid]]></c> | <c><![CDATA[is_port]]></c> | + <c><![CDATA[is_reference]]></c> | <c><![CDATA[is_tuple]]></c> | <c><![CDATA[is_binary]]></c> | + <c><![CDATA[is_function]]></c> | <c><![CDATA[is_record]]></c> | <c><![CDATA[is_seq_trace]]></c> | + <c><![CDATA['and']]></c> | <c><![CDATA['or']]></c> | <c><![CDATA['not']]></c> | <c><![CDATA['xor']]></c> | + <c><![CDATA[andalso]]></c> | <c><![CDATA[orelse]]></c></item> + <item>ConditionExpression ::= ExprMatchVariable | { GuardFunction } | + { GuardFunction, ConditionExpression, ... } | TermConstruct + </item> + <item>ExprMatchVariable ::= MatchVariable (bound in the MatchHead) | + <c><![CDATA['$_']]></c> | <c><![CDATA['$$']]></c></item> + <item>TermConstruct = {{}} | {{ ConditionExpression, ... }} | + <c><![CDATA[[]]]></c> | [ConditionExpression, ...] | NonCompositeTerm | Constant + </item> + <item>NonCompositeTerm ::= term() (not list or tuple) + </item> + <item>Constant ::= {<c><![CDATA[const]]></c>, term()} + </item> + <item>GuardFunction ::= BoolFunction | <c><![CDATA[abs]]></c> | + <c><![CDATA[element]]></c> | <c><![CDATA[hd]]></c> | <c><![CDATA[length]]></c> | <c><![CDATA[node]]></c> | + <c><![CDATA[round]]></c> | <c><![CDATA[size]]></c> | <c><![CDATA[tl]]></c> | <c><![CDATA[trunc]]></c> | + <c><![CDATA['+']]></c> | <c><![CDATA['-']]></c> | <c><![CDATA['*']]></c> | <c><![CDATA['div']]></c> | + <c><![CDATA['rem']]></c> | <c><![CDATA['band']]></c> | <c><![CDATA['bor']]></c> | <c><![CDATA['bxor']]></c> | + <c><![CDATA['bnot']]></c> | <c><![CDATA['bsl']]></c> | <c><![CDATA['bsr']]></c> | <c><![CDATA['>']]></c> | + <c><![CDATA['>=']]></c> | <c><![CDATA['<']]></c> | <c><![CDATA['=<']]></c> | <c><![CDATA['=:=']]></c> | + <c><![CDATA['==']]></c> | <c><![CDATA['=/=']]></c> | <c><![CDATA['/=']]></c> | <c><![CDATA[self]]></c> | + <c><![CDATA[get_tcw]]></c></item> + <item>MatchBody ::= [ ConditionExpression, ... ]</item> + </list> </section> <section> @@ -453,8 +499,8 @@ <section> <title>Differences between match specifications in ETS and tracing</title> <p>ETS match specifications are there to produce a return - value. Usually the expression contains one single - <c><![CDATA[ActionTerm]]></c> which defines the return value without having + value. Usually the <c><![CDATA[MatchBody]]></c> contains one single + <c><![CDATA[ConditionExpression]]></c> which defines the return value without having any side effects. Calls with side effects are not allowed in the ETS context.</p> <p>When tracing there is no return value to produce, the @@ -530,7 +576,7 @@ the atom 'strider' and the tuple arity is 3 and return the whole object.</p> <code type="none"><![CDATA[ -[{{strider,'_'.'_'}, +[{{strider,'_','_'}, [], ['$_']}] ]]></code> |