add partcont library

contrib/partcont/CMakeLists.txt

@@ -0,0 +1,2 @@
+file(GLOB PARTCONT_FILES ${PROJECT_SOURCE_DIR}/contrib/partcont/piclib/*.scm)
+list(APPEND PICLIB_CONTRIB_LIBS ${PARTCONT_FILES})

contrib/partcont/piclib/partcont.scm

@@ -0,0 +1,28 @@
+(define-library (picrin control)
+  (import (scheme base))
+
+  (define m #f)
+
+  (define (reset t)
+    (call/cc
+     (lambda (k)
+       (let ((n m))
+         (set! m (lambda (r)
+                   (set! m n)
+                   (k r)))
+         (t)))))
+
+  (define (shift h)
+    (call/cc
+     (lambda (k)
+       (h (lambda (v)
+            (reset (lambda ()
+                     (k v))))))))
+
+  (define prompt reset)
+  (define control shift)
+
+  (export shift
+          reset
+          control
+          prompt))

src/CMakeLists.txt

@@ -9,6 +9,8 @@ set(XFILE_SOURCES extlib/xfile/xfile.c)
 # piclib
 find_package(Perl REQUIRED)
 file(GLOB_RECURSE PICLIB_SCHEME_LIBS ${PROJECT_SOURCE_DIR}/piclib/*.scm)
+list(APPEND PICLIBS ${PICLIB_SCHEME_LIBS})
+list(APPEND PICLIBS ${PICLIB_CONTRIB_LIBS})
 set(PICLIB_SOURCES ${PROJECT_SOURCE_DIR}/src/load_piclib.c)
 add_custom_command(
   OUTPUT ${PICLIB_SOURCES}