initial commit of a regex match? function

1 files changed, 52 insertions, 0 deletions

diff --git a/libs/regex.neb b/libs/regex.neb
new file mode 100644
index 0000000..e6bff34
--- /dev/null
+++ b/libs/regex.neb
@@ -0,0 +1,52 @@
+; regex
+; for doing regex matches
+
+(func match? :bool (pattern :string text :string)
+    
+    (func match-one :bool (left right)
+        (in? left (list "" "." right)))
+
+    (func match-? :bool (pattern text)
+        (or
+            (and 
+                (match-one (first-char pattern) (first-char text))
+                (match-inner (rest-char (rest-char pattern)) (rest-char text)))
+            (match-inner (rest-char (rest-char pattern)) text)))
+
+    (func match-* (pattern text)
+        (or
+            (and
+                (match-one (first-char pattern) (first-char text))
+                (match-inner pattern (rest-char text)))
+            (match-inner (rest-char (rest-char pattern)) text)))
+
+    (func match-inner (pattern text)
+        (branch
+            ((eq? "" pattern) #true)
+            ((and (eq? "$" pattern) (eq? "" text)) #true)
+            ((eq? "" text) #false)
+            ((and (>= (length pattern) 2) (eq? "?" (first-char (rest-char pattern))))
+                (match-? pattern text))
+            ((and (>= (length pattern) 2) (eq? "*" (first-char (rest-char pattern))))
+                (match-* pattern text))
+            (#true
+                (and
+                    (match-one (first-char pattern) (first-char text))
+                    (match-inner (rest-char pattern) (rest-char text))))))
+
+    (func search (pattern text)
+        (if (eq? "^" (first-char pattern))
+            (match-inner (rest-char pattern) text)
+            (block
+                (def progress text)
+                (def out (list))
+                (for-count (length text)
+                    (redef out (append out (match-inner pattern progress)))
+                    (redef progress (rest-char progress)))
+                (or
+                    (eq? 0 (list-length out))
+                    (if (eq? 1 (list-length out))
+                        (first out)
+                        (apply or out))))))
+
+    (search pattern text))