Clojure JIRA

[MATCH-36] throw on unsuccessful match

Wed, 30 Nov 2011 20:46:39 -0600

I was on the fence about this. But after looking at the literature as well as the behavior of condp, I've decided that throwing on unsuccessful match is the way to go. This is particularly important since we put no constraints on the types allowed - we cannot determine exhaustiveness.

[MATCH-31] vector patterns should work on seq

Wed, 30 Nov 2011 20:46:21 -0600

This means abandoning subvec and using nth + offsets.

[MATCH-47] vector patterns dispatch on count after dispatching on type

Fri, 23 Dec 2011 22:22:41 -0600

The current behavior just creates complications.

[MATCH-35] Bug in seq pattern matching

Wed, 11 Jan 2012 10:26:35 -0600

(let [l '(1 2 3)]
    (match [l]
      [([a & [b & [c d]]] :seq)] :a0
      :else :a1))

Matches when it shouldn't.

[MATCH-4] Optimized pattern matching on deftype/record, POJOs

Thu, 27 Oct 2011 23:42:15 -0500

(match [x]
  [({:a 0 :b 1} :type Foo)] :a0
  ...)

:a and :b would be converted to field access, i.e. (.a x)

As with primitive array matching, we should do an instance check followed by hinted field access.

We should consider adopting the deftype/record syntax.

[MATCH-2] Matching Diagnostics

Thu, 27 Oct 2011 23:50:44 -0500

Communicate to the user precisely what failed to match. Conversation here: http://groups.google.com/group/clojure/browse_thread/thread/675456fba1712214. We adopt the behavior of condp since that is closer to what match does and will do (predicate dispatch)

[MATCH-40] Allow or'ing of guard functions

Mon, 21 Nov 2011 11:11:42 -0600

In order to simplify composition of guard predicates which are alternatives, allow for passing a sequence of predicates whose values when called will be or'd together.

The :when keyword currently allows passing of a vector of predicates that are and'd together.

Either case (`and` or `or`) can be achieved externally to match via composition, and an alternative might be to force explicit composition outside of core.match.

At the least, the documentation should mention that multiple predicates will be and'd together.

[MATCH-39] Allow matching of map expressions to restrict the set of keys present in the value to a subset of a specified set of keys

Mon, 21 Nov 2011 12:34:22 -0600

It is useful, to be able to constrain a match on a map value to limit the set of keys present in the value, without enforcing that the keys are all present in the value.

The current :only option, enforces a strict matching of keys.

{{(let [x {:a 1} (match [x] [({:a _ :b _} :only [:a :b])])}} => doesn't match

This came up trying to write a precondition on the argument of a function, which allowed optional keys, but wanted to restrict the overall set of keys.

[MATCH-55] Matching a sequence with just a rest pattern fails to compile

Wed, 21 Mar 2012 15:37:19 -0500

In 0.2.0-alpha9,

(match [ [1 2] ] [([& _] :seq)] true)

fails to compile with No method in multimethod 'to-source' for dispatch value: class clojure.core.match.RestPattern

[MATCH-56] IndexOutOfBoundsException when matching empty vector

Tue, 27 Mar 2012 10:28:38 -0500

Using the latest core.match:

user=> (let [x []] (match [x] [[h & t]] [h t] :else :nomatch))
IndexOutOfBoundsException clojure.lang.RT.subvec (RT.java:1451)

Not sure if this is the best fix, but I resolved this specific case by slightly changing subvec-inline (see attached diff).

[MATCH-58] we should test the presence of key with find, not get

Sat, 7 Apr 2012 19:34:26 -0500

If a user really doesn't care about the existence of a key they won't match on it. The current behavior is very confusing.

[MATCH-61] Exception thrown when matching using :seq when there is a seq call in the tail of the occurrences

Fri, 22 Jun 2012 17:33:34 -0500

I also tested with three occurrences. When there is a seq call in the second occurrence onward a RuntimeException is thrown.

[MATCH-49] Duplicate wildcard detection in pattern row doesn't account for locals

Thu, 12 Jan 2012 08:36:14 -0600

Duplicate wildcard detection in pattern row doesn't account for locals

[MATCH-64] Improve match compile times

Wed, 15 Aug 2012 13:04:32 -0500

Improve match compile times

[MATCH-65] cata matching

Fri, 23 Nov 2012 16:54:30 -0600

Dan Friedman's pattern matcher has a nice feature called cata-matching - allowing recursive matching from the match itself. Useful when writing compilers.

[MATCH-63] IllegalArgumentException when AOT compiling namespace using clojure.core.match since alpha10

Tue, 26 Feb 2013 13:55:26 -0600

Getting this when AOT compiling a trivial project (attached) using alpha10: (works fine with alpha9)

Caused by: java.lang.IllegalArgumentException: No method in multimethod 'to-source' for dispatch value: class clojure.core.match.WildcardPattern
	at clojure.lang.MultiFn.getFn(MultiFn.java:121)
	at clojure.lang.MultiFn.invoke(MultiFn.java:167)
	at clojure.core.match$dag_clause_to_clj.invoke(match.clj:424)
	at clojure.lang.AFn.applyToHelper(AFn.java:167)
	at clojure.lang.AFn.applyTo(AFn.java:151)
	at clojure.core$apply.invoke(core.clj:602)
	at clojure.lang.AFn.applyToHelper(AFn.java:167)
	at clojure.lang.RestFn.applyTo(RestFn.java:132)
	at clojure.core$apply.invoke(core.clj:604)
	at clojure.core$partial$fn__3796.doInvoke(core.clj:2343)
	at clojure.lang.RestFn.invoke(RestFn.java:408)
	at clojure.core$map$fn__3811.invoke(core.clj:2430)
	at clojure.lang.LazySeq.sval(LazySeq.java:42)
	at clojure.lang.LazySeq.seq(LazySeq.java:60)
	at clojure.lang.RT.seq(RT.java:466)
	at clojure.core$seq.invoke(core.clj:133)
	at clojure.core$apply.invoke(core.clj:600)
	at clojure.core$mapcat.doInvoke(core.clj:2459)
	at clojure.lang.RestFn.invoke(RestFn.java:423)
	at clojure.core.match.SwitchNode.n_to_clj(match.clj:446)
	at clojure.core.match.BindNode.n_to_clj(match.clj:411)
	at clojure.core.match$executable_form.invoke(match.clj:1713)
	at clojure.core.match$clj_form.invoke(match.clj:1721)
	at clojure.core.match$match.doInvoke(match.clj:1750)

[MATCH-69] AOT-compiling match expression produces stack overflow

Wed, 24 Apr 2013 16:04:23 -0500

The offending match expression is pretty gnarly, will try to simplify and post it here later. For now, a (partial) stack trace, eliding the repeating bits:

Caused by: java.lang.StackOverflowError
	at clojure.core$map$fn__4207.invoke(core.clj:2479)
	at clojure.lang.LazySeq.sval(LazySeq.java:42)
	at clojure.lang.LazySeq.seq(LazySeq.java:60)
	at clojure.lang.ChunkedCons.chunkedNext(ChunkedCons.java:59)
	at clojure.lang.ChunkedCons.next(ChunkedCons.java:43)
	at clojure.lang.PersistentVector.create(PersistentVector.java:51)
	at clojure.lang.LazilyPersistentVector.create(LazilyPersistentVector.java:31)
	at clojure.core$vec.invoke(core.clj:354)
	at clojure.core.match.PatternMatrix.column(match.clj:713)
	at clojure.core.match$useful_p_QMARK_.invoke(match.clj:811)
	at clojure.core.match.PatternMatrix$iter__1458__1464$fn__1465$iter__1460__1466$fn__1467$fn__1468.invoke(match.clj:765)
	at clojure.core.match.PatternMatrix$iter__1458__1464$fn__1465$iter__1460__1466$fn__1467.invoke(match.clj:763)
	at clojure.lang.LazySeq.sval(LazySeq.java:42)
	at clojure.lang.LazySeq.seq(LazySeq.java:60)
	at clojure.lang.RT.seq(RT.java:484)
	at clojure.core$seq.invoke(core.clj:133)
	at clojure.core.match.PatternMatrix$iter__1458__1464$fn__1465.invoke(match.clj:764)
	at clojure.lang.LazySeq.sval(LazySeq.java:42)
	at clojure.lang.LazySeq.seq(LazySeq.java:67)
	at clojure.lang.RT.seq(RT.java:484)
	at clojure.core$seq.invoke(core.clj:133)
	at clojure.core$partition$fn__4309.invoke(core.clj:2834)
	at clojure.lang.LazySeq.sval(LazySeq.java:42)
	at clojure.lang.LazySeq.seq(LazySeq.java:60)
	at clojure.lang.RT.seq(RT.java:484)
	at clojure.core$seq.invoke(core.clj:133)
	at clojure.core$map$fn__4207.invoke(core.clj:2479)
	at clojure.lang.LazySeq.sval(LazySeq.java:42)
	at clojure.lang.LazySeq.seq(LazySeq.java:60)
	at clojure.lang.Cons.next(Cons.java:39)
	at clojure.lang.PersistentVector.create(PersistentVector.java:51)
	at clojure.lang.LazilyPersistentVector.create(LazilyPersistentVector.java:31)
	at clojure.core$vec.invoke(core.clj:354)
	at clojure.core.match.PatternMatrix.useful_matrix(match.clj:763)
	at clojure.core.match.PatternMatrix.necessary_column(match.clj:755)
	at clojure.core.match.PatternMatrix$choose_column__1441.invoke(match.clj:720)
	at clojure.core.match.PatternMatrix.compile(match.clj:738)
	at clojure.core.match$first_column_chosen_case$switch_clauses__1406$fn__1407.invoke(match.clj:643)
	at clojure.core$map$fn__4211.invoke(core.clj:2492)
	at clojure.lang.LazySeq.sval(LazySeq.java:42)
	at clojure.lang.LazySeq.seq(LazySeq.java:60)
	at clojure.lang.RT.seq(RT.java:484)
	at clojure.core$seq.invoke(core.clj:133)
	at clojure.core.protocols$seq_reduce.invoke(protocols.clj:30)
	at clojure.core.protocols$fn__6026.invoke(protocols.clj:54)
	at clojure.core.protocols$fn__5979$G__5974__5992.invoke(protocols.clj:13)
	at clojure.core$reduce.invoke(core.clj:6177)
	at clojure.core$into.invoke(core.clj:6229)
	at clojure.core.match$first_column_chosen_case$switch_clauses__1406.invoke(match.clj:646)
	at clojure.core.match$first_column_chosen_case.invoke(match.clj:676)
	at clojure.core.match.PatternMatrix.compile(match.clj:740)
	at clojure.core.match$first_column_chosen_case$switch_clauses__1406$fn__1407.invoke(match.clj:643)
	at clojure.core$map$fn__4211.invoke(core.clj:2492)
	at clojure.lang.LazySeq.sval(LazySeq.java:42)
	at clojure.lang.LazySeq.seq(LazySeq.java:60)
	at clojure.lang.RT.seq(RT.java:484)
	at clojure.core$seq.invoke(core.clj:133)
	at clojure.core.protocols$seq_reduce.invoke(protocols.clj:30)
	at clojure.core.protocols$fn__6026.invoke(protocols.clj:54)
	at clojure.core.protocols$fn__5979$G__5974__5992.invoke(protocols.clj:13)
	at clojure.core$reduce.invoke(core.clj:6177)
	at clojure.core$into.invoke(core.clj:6229)

[MATCH-54] Cannot AOT with certain match expression.

Sat, 18 May 2013 14:22:38 -0500

If you try to AOT this code, you get an exception.

(defn -main [& args]
  (println args)
  (let [x nil] 
    (match x
      ["=" _ _] true
      [[:invoke _] _] true)))

Stack Trace:

Compiling foo.core
Exception in thread "main" java.lang.IndexOutOfBoundsException, compiling:(foo/core.clj:8)
	at clojure.lang.Compiler.analyzeSeq(Compiler.java:6416)
	at clojure.lang.Compiler.analyze(Compiler.java:6216)
	at clojure.lang.Compiler.analyze(Compiler.java:6177)
	at clojure.lang.Compiler$BodyExpr$Parser.parse(Compiler.java:5572)
	at clojure.lang.Compiler$LetExpr$Parser.parse(Compiler.java:5873)
	at clojure.lang.Compiler.analyzeSeq(Compiler.java:6409)
	at clojure.lang.Compiler.analyze(Compiler.java:6216)
	at clojure.lang.Compiler.analyzeSeq(Compiler.java:6397)
	at clojure.lang.Compiler.analyze(Compiler.java:6216)
	at clojure.lang.Compiler.analyze(Compiler.java:6177)
	at clojure.lang.Compiler$BodyExpr$Parser.parse(Compiler.java:5572)
	at clojure.lang.Compiler$FnMethod.parse(Compiler.java:5008)
	at clojure.lang.Compiler$FnExpr.parse(Compiler.java:3629)
	at clojure.lang.Compiler.analyzeSeq(Compiler.java:6407)
	at clojure.lang.Compiler.analyze(Compiler.java:6216)
	at clojure.lang.Compiler.analyzeSeq(Compiler.java:6397)
	at clojure.lang.Compiler.analyze(Compiler.java:6216)
	at clojure.lang.Compiler.access$100(Compiler.java:37)
	at clojure.lang.Compiler$DefExpr$Parser.parse(Compiler.java:492)
	at clojure.lang.Compiler.analyzeSeq(Compiler.java:6409)
	at clojure.lang.Compiler.analyze(Compiler.java:6216)
	at clojure.lang.Compiler.analyze(Compiler.java:6177)
	at clojure.lang.Compiler.compile1(Compiler.java:6980)
	at clojure.lang.Compiler.compile(Compiler.java:7046)
	at clojure.lang.RT.compile(RT.java:385)
	at clojure.lang.RT.load(RT.java:425)
	at clojure.lang.RT.load(RT.java:398)
	at clojure.core$load$fn__4610.invoke(core.clj:5386)
	at clojure.core$load.doInvoke(core.clj:5385)
	at clojure.lang.RestFn.invoke(RestFn.java:408)
	at clojure.core$load_one.invoke(core.clj:5200)
	at clojure.core$compile$fn__4615.invoke(core.clj:5397)
	at clojure.core$compile.invoke(core.clj:5396)
	at user$eval27.invoke(NO_SOURCE_FILE:1)
	at clojure.lang.Compiler.eval(Compiler.java:6465)
	at clojure.lang.Compiler.eval(Compiler.java:6455)
	at clojure.lang.Compiler.eval(Compiler.java:6431)
	at clojure.core$eval.invoke(core.clj:2795)
	at clojure.main$eval_opt.invoke(main.clj:296)
	at clojure.main$initialize.invoke(main.clj:315)
	at clojure.main$null_opt.invoke(main.clj:348)
	at clojure.main$main.doInvoke(main.clj:426)
	at clojure.lang.RestFn.invoke(RestFn.java:421)
	at clojure.lang.Var.invoke(Var.java:405)
	at clojure.lang.AFn.applyToHelper(AFn.java:163)
	at clojure.lang.Var.applyTo(Var.java:518)
	at clojure.main.main(main.java:37)
Caused by: java.lang.IndexOutOfBoundsException
	at clojure.lang.PersistentVector.arrayFor(PersistentVector.java:106)
	at clojure.lang.PersistentVector.nth(PersistentVector.java:110)
	at clojure.lang.RT.nth(RT.java:741)
	at clojure.core.match.PatternRow.invoke(match.clj:327)
	at clojure.core.match.PatternMatrix.pattern_at(match.clj:713)
	at clojure.core.match$useful_p_QMARK_.invoke(match.clj:778)
	at clojure.core.match.PatternMatrix$iter__832__838$fn__839$iter__834__840$fn__841$fn__842.invoke(match.clj:735)
	at clojure.core.match.PatternMatrix$iter__832__838$fn__839$iter__834__840$fn__841.invoke(match.clj:733)
	at clojure.lang.LazySeq.sval(LazySeq.java:42)
	at clojure.lang.LazySeq.seq(LazySeq.java:60)
	at clojure.lang.RT.seq(RT.java:466)
	at clojure.core$seq.invoke(core.clj:133)
	at clojure.core.match.PatternMatrix$iter__832__838$fn__839.invoke(match.clj:734)
	at clojure.lang.LazySeq.sval(LazySeq.java:42)
	at clojure.lang.LazySeq.seq(LazySeq.java:67)
	at clojure.lang.RT.seq(RT.java:466)
	at clojure.core$seq.invoke(core.clj:133)
	at clojure.core$partition$fn__3913.invoke(core.clj:2777)
	at clojure.lang.LazySeq.sval(LazySeq.java:42)
	at clojure.lang.LazySeq.seq(LazySeq.java:60)
	at clojure.lang.RT.seq(RT.java:466)
	at clojure.core$seq.invoke(core.clj:133)
	at clojure.core$map$fn__3811.invoke(core.clj:2424)
	at clojure.lang.LazySeq.sval(LazySeq.java:42)
	at clojure.lang.LazySeq.seq(LazySeq.java:60)
	at clojure.lang.Cons.next(Cons.java:39)
	at clojure.lang.PersistentVector.create(PersistentVector.java:50)
	at clojure.lang.LazilyPersistentVector.create(LazilyPersistentVector.java:31)
	at clojure.core$vec.invoke(core.clj:345)
	at clojure.core.match.PatternMatrix.useful_matrix(match.clj:733)
	at clojure.core.match.PatternMatrix.necessary_column(match.clj:725)
	at clojure.core.match.PatternMatrix$choose_column__815.invoke(match.clj:690)
	at clojure.core.match.PatternMatrix.compile(match.clj:708)
	at clojure.core.match$first_column_chosen_case$switch_clauses__780$fn__781.invoke(match.clj:613)
	at clojure.core$map$fn__3815.invoke(core.clj:2437)
	at clojure.lang.LazySeq.sval(LazySeq.java:42)
	at clojure.lang.LazySeq.seq(LazySeq.java:60)
	at clojure.lang.RT.seq(RT.java:466)
	at clojure.core$seq.invoke(core.clj:133)
	at clojure.core$reduce.invoke(core.clj:5994)
	at clojure.core$into.invoke(core.clj:6004)
	at clojure.core.match$first_column_chosen_case$switch_clauses__780.invoke(match.clj:616)
	at clojure.core.match$first_column_chosen_case.invoke(match.clj:646)
	at clojure.core.match.PatternMatrix.compile(match.clj:710)
	at clojure.core.match$first_column_chosen_case$switch_clauses__780$fn__781.invoke(match.clj:613)
	at clojure.core$map$fn__3815.invoke(core.clj:2437)
	at clojure.lang.LazySeq.sval(LazySeq.java:42)
	at clojure.lang.LazySeq.seq(LazySeq.java:60)
	at clojure.lang.RT.seq(RT.java:466)
	at clojure.core$seq.invoke(core.clj:133)
	at clojure.core$reduce.invoke(core.clj:5994)
	at clojure.core$into.invoke(core.clj:6004)
	at clojure.core.match$first_column_chosen_case$switch_clauses__780.invoke(match.clj:616)
	at clojure.core.match$first_column_chosen_case.invoke(match.clj:646)
	at clojure.core.match.PatternMatrix.compile(match.clj:710)
	at clojure.core.match$clj_form.invoke(match.clj:1616)
	at clojure.core.match$match.doInvoke(match.clj:1645)
	at clojure.lang.RestFn.invoke(RestFn.java:573)
	at clojure.lang.Var.invoke(Var.java:426)
	at clojure.lang.AFn.applyToHelper(AFn.java:193)
	at clojure.lang.Var.applyTo(Var.java:518)
	at clojure.lang.Compiler.macroexpand1(Compiler.java:6320)
	at clojure.lang.Compiler.analyzeSeq(Compiler.java:6395)
	... 46 more

[MATCH-51] Fail to match empty vector

Sat, 18 May 2013 14:24:24 -0500

(match (vector)
  ([(re :guard string?)] :seq) 4
  [] 6)

This should evaluate to 6 not nil.

[MATCH-53] Match doesn't work when AOT compiled into a JAR, but manually macroexpanding and JAR'ing works fine.

Sat, 18 May 2013 14:25:39 -0500

Code here:

https://gist.github.com/35fa11df7d7516abff50

Running lein uberjar on source containing the offending function, geo->svg, results in a non-working application.
However, if match is manually macroexpanded in the repl and the results pasted in, then the JAR works just fine.

[MATCH-57] Non deterministic match behavior for seqs when AOT

Sat, 18 May 2013 14:29:42 -0500

The following source example:

https://github.com/narkisr/match-issue/blob/master/src/match_issue/core.clj

The defrule macro calls a function called lhs that use the match library,

this function calls it self recursively and print out the rest of body left to be matched,

When running lein compile two different results appear (in non deterministic fashion):

(when $message :> Message (== level 6) :from (entry-point event-stream))
($message :> Message (== level 6) :from (entry-point event-stream))
(Message (== level 6) :from (entry-point event-stream))
((== level 6) :from (entry-point event-stream))

This is the bug, as (== level 6) should be matched by:

[([([(o :when operator?) f s] :seq) :as c & r] :seq)]

In other cases the output is (the correct one):

[MATCH-68] Vector match "underflow" => IndexOutOfBoundsException

Sat, 18 May 2013 15:11:12 -0500

This fails with 0.2.0-alpha12:

(match [[:x]]
  [[m n & _]] 1)

I expect nil, but an unguarded subvec call throws an IndexOutOfBoundsException.

A WIP patch is attached that fixes this (perhaps incorrectly) but which produced regressions (outside of core.match), e.g.

(match [[[:x "t"]]]
 [[[:x & a] & tail]] :a
 [[[:y & p] [:x & a] & tail]] :b)
=> nil

The patch also "fixes" this (by changing pattern-compare behaviour for rest VectorPattern s, but that leads to a regression in the vector-pattern-rest-2 testcase in core.match.

(Original discussion with further background here.)

[MATCH-8] Implement (p|q)ba heuristics

Sun, 4 Sep 2011 10:00:57 -0500

We should implement the rest of Maranget's suggested heuristics.

p - needed prefix
q - constructor prefix
b - branching factor
a - constructor arity

[MATCH-9] use case for dispatching on literals

Mon, 10 Oct 2011 22:45:51 -0500

Would speed up literal matching considerably.

[MATCH-7] Eliminate distinction between leaf-bind-expr and bind-expr

Fri, 21 Oct 2011 18:55:52 -0500

We should have a better considered binding model that works for all cases instead of treating leaf nodes and regular binding as different cases.