another example

2 files changed, 36 insertions, 2 deletions

diff --git a/README.md b/README.md
index 377a5ac..87767c4 100644
--- a/README.md
+++ b/README.md
@@ -64,7 +64,30 @@ apears at the end of the document, following the tutorial.
 > (car (pick-out '(40) (fibs))) ;; 267914296
 
 ```
-    
+
+### A Kind Of Grep
+
+``` lisp
+
+
+> (defmacro a-kind-of-grep (match-var key file &rest body)
+   `(for ,match-var (filter! (lambda (line) (search ,key line))
+                             (file-lines ,file))
+      ,@body))
+
+;; look for export lines in my .bashrc
+
+> (let ((count 0))
+    (a-kind-of-grep line "export" "~/.bashrc" 
+        (incf count)
+        (print line)))
+      
+"export PATH=$HOME/.roswell/bin:$PATH" 
+"export PATH=$HOME/.local/bin:$PATH" 
+2
+
+```
+
 ## Tutorial
 
 GTWIWTG is a tiny library for creating and using generators. 
diff --git a/examples.lisp b/examples.lisp
index 83ba5c8..6d2f570 100644
--- a/examples.lisp
+++ b/examples.lisp
@@ -3,7 +3,8 @@
   (:export
    #:perms
    #:all-primes
-   #:fibs))
+   #:fibs
+   #:a-kind-of-grep))
 
 (in-package :gtwiwtg.examples)
 
@@ -109,3 +110,13 @@ vector VEC, one at a time."
 ;;                   subperms))))
 ;;
 ;; which looks a little nicer but is less kind to the heap and to GC.
+
+;;; A kind of Grep ;;;
+
+(defmacro a-kind-of-grep (match-var key file &rest body)
+  `(for ,match-var (filter! (lambda (line) (search ,key line))
+                            (file-lines ,file))
+     ,@body))
+
+
+;; find all export expressions in my bashrc file