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--- groimp-platform:xl-operators [2024/05/02 10:12] – [Other] TimOb
+++ groimp-platform:xl-operators [2025/01/10 15:08] (current) – [Pattern predicates] gaetan
@@ Line 1: / Line 1: @@
-XL-Operators are designed to simplify the usage of XL queries and rewriting rules. Moreover these operators can improve the performance of a query due to there deep integration into the model.
+===== Production operators =====
-In the following the operators a separated into Analytical and selection operators to either get a value for analysis or a node/ a collection of nodes for rewriting.
-====== Analytical Operators ======
+Production operators are operators that can be used in a production statement.
-| Command | description | example |
+==== Edge operators ====
-| min((*//query//*)[//value//]) | returns the smallest value | min((*F*)[length]) |
-| max((*//query//*)[//value//]) | returns the largest value | max((*F*)[length]) |
-| sum((*//query//*)[//value//]) | calculate the sum of the values | sum((*F*)[length]) |
-| prod((*//query//*)[//value//]) | unclear | prod((*F*)[length]) |
-| count((*//query//*) )| returns the number of pattern matching the query | count((*F*) ) |
-| empty((*//query//*) ) | returns true if no pattern matches the query | empty((*F*) ) |
-| forall((*//query//*)[//value//]//condition//) | checks if a condition is true for the all results of the query |forall((*f:F*)[length]==1) |
-| exist((*//query//*)[//value//]//condition//) | checks if a condition is true for at least one result of the query |exist((*f:F*)[length]==1) |
+| whitespace | add node and connect with previous node, if any, by a successor edge |
+| > | connect node with previous by a successor edge |
-====== Selection Operators ======
+| < | connect node with previous by a reverse successor edge |
+| %%<->%% | connect node with previous by successor edges in both directions |
-| command | description| example|
+| %%---%% | connect node with previous by a successor edge if there does not yet exist such an edge in either direction |
-| first((*//query//*) ) | get the first element found with the query | first((*F*) ) |
+| %%+>%%, %%<+%%, %%<+>%%, %%-+-%% | as before, but branch instead of successor edges |
-| last((*//query//*) ) | get the last element found with the query | last((*F*) ) |
+| %%/>%%, %%</%%, %%</>%%, %%-/-%% | as before, but refinement instead of successor edges |
-|selectWhere((*//query//*),//condition//)| Select a node of the query that fits the condition | selectWhere((*f:F*),f[length]==1) |
+| %%-e->%%, %%<-e-%%, %%<-e->%%, %%-e-%% with an int-valued expression e | as before, but edges of type e instead of successor edges |
-|selectWhereMin((*//query//*),//parameter//)| Select a node of the query where the parameter is the smallest | selectWhereMin((*f:F*),f[length])  |
+| %%-n->%% with a node-valued expression n | create a compound edge with n encoding the edge data |
-|selectWhereMax((*//query//*),//parameter//)| Select a node of the query where the parameter is the largest | selectWhereMax((*f:F*),f[length]) |
+| %%<-n-%% with a node-valued expression n | as before, but reverse direction |
-|selectRandomly((*//query//*) )| select a Random node from the query | selectRandomly((*F*) ) |
+| [, ] | define the starts and the end of a branch connected subgraph |
-|selectRandomly((*//query//*),prob)| ??? | ???  |
-====== Other ======
-|command | description|example|
-| array((*//query//*) ) | creates an java array of the items or values  | array((*F*) ), array((*F*)[length]) |
-| string((*//query//*) ) | creates an comma separated string of the items or values  | string((*F*) ), string((*F*)[length]) |