templates: add match function

Add a match function that returns true if a string matches the provided
regular expression. The compiled regular expressions are cached in
a sync.Map to avoid repetitive compilations of the same expressions.

Caveat: if the user mixes the arguments order, it may cause the cache to
consume a lot of memory filled with garbage regular expression objects.
Ideally, we would need to limit the size of this cache and/or use a LRU
cache implementation. Maybe someday?

Signed-off-by: Robin Jarry <robin@jarry.cc>
Acked-by: Tim Culverhouse <tim@timculverhouse.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/lib/templates/functions.go b/lib/templates/functions.go
index 1cbdc85d..8bd8f37b 100644
--- a/lib/templates/functions.go
+++ b/lib/templates/functions.go
@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"git.sr.ht/~rjarry/aerc/lib/format"
+	"git.sr.ht/~rjarry/aerc/lib/parse"
 	"github.com/emersion/go-message/mail"
 )
 
@@ -271,4 +272,5 @@ var templateFuncs = template.FuncMap{
 	"join":          join,
 	"trimSignature": trimSignature,
 	"compactDir":    compactDir,
+	"match":         parse.MatchCache,
 }