Background : initial question: http://forum.world.st/RewriteTool-matching-parts-of-an-array-tp4910482.html my fix : 18910 <https://pharo.fogbugz.com/f/cases/18910/MNU-OrderedCollection-parent-when-tr...> MNU: OrderedCollection>>parent: when trying to rewrite a tree with RBParseTreeRewriter the error my fix introduced :-) : 19445 <https://pharo.fogbugz.com/f/cases/19445/Pattern-code-ArrayNode-matching-fail...> Pattern code ArrayNode matching failure Question : how should a pattern with three variables (first/second/third) look like to match the expression { (1@2) . Color red . 3} and assign the (sub)-expressions 1@2 Color red 3 to the three variables first/second/third ? Looking at the initial question "RegisterRewriteTool matching parts of an array", I was suprised that for the pattern and the dynamic array expression: pattern := '{ `@first . `@second . `@third }' expression := '{ (1@2) . Color red . 3}' the third variable matches all three expressions and the first two are empty: RBPatternVariableNode(`@first)->an OrderedCollection() RBPatternVariableNode(`@second)->an OrderedCollection() RBPatternVariableNode(`@third)->an OrderedCollection(RBMessageNode((1 @ 2)) RBMessageNode(Color red) RBLiteralValueNode(3)) I fixed this in a way, that all three variables gets assigned one (sub)expression of the array. But the fix was wrong, now a statement-list-pattern-variable cannot be used anymore to match the array statements: pattern := '{ `@.stmts }'. expression:= RBParser parseExpression:'{ (1@2) . Color red . 3}'. results in an error during matching but I would expect the result: RBPatternVariableNode(`@.stmts)->an OrderedCollection(RBMessageNode((1 @ 2)) RBMessageNode(Color red) RBLiteralValueNode(3)) Now I am not sure that the pattern { `@first . `@second . `@third }' is actually a valid pattern for matching the array (sub)-expressions, the array contents is a list of three single statemts and @first isn't a statement pattern, but a pattern for an expression list. On the other hand, if I try to match *three statements* without the being in a dynamic array: (Note the missing curly braces) pattern := '`@first . `@second . `@third '. expression : parseExpression: ' (1@2) . Color red . 3'. The result works as I wanted them for the array pattern: RBPatternVariableNode(`@first)->RBMessageNode(1 @ 2) RBPatternVariableNode(`@second)->RBMessageNode(Color red) RBPatternVariableNode(`@third)->RBLiteralValueNode(3) So, is the pattern actually right or is the matching wrong? What should I expect by these patterns and expressions: pattern := '`@first . `@second . `@third '. expression : parseExpression: ' (1@2) . Color red . 3'. pattern := '`.first. `.second. `.third. '. expression := ' (1@2) . Color red . 3'. pattern := '{`.first. `.second. `.third.}'. expression := '{ (1@2) . Color red . 3}'. pattern := '{`@.all}'. expression := '{ (1@2) . Color red . 3}'. pattern := '{`@.all}'. expression := '{ (1@2) . Color red . 3}'. pattern := '`.head. `.@tail'. expression := '(1@2) . Color red . 3'. pattern := '{`.head. `.@tail}'. expression := '{(1@2) . Color red . 3}'. I would expect all statement-pattern without the dynamic array, assign the variables to the subexpressions, and the same way for the pattern with dynamic arrays. Btw, I don't know why this does not match pattern := '`.head `.@tail'. expression := '(1@2) . Color red . 3'. isn't the first variable a statement pattern ?
From the rewrite-tool documentation ( http://www.refactory.com/tools/refactoring-browser/rewrite-tool):
` recurse into the thing that is matched looking for more matches @ treat the item as a list ; used for messages where the message is treated as a list of messages in a cascade . treat the item as a statement in a sequence node # matches literals thanks in advance nicolai