Implement tasks and plays

modules/ordo/context.scm

@@ -0,0 +1,40 @@
+(define-module (ordo context)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-9)
+  #:use-module (srfi srfi-26)
+  #:export (make-context
+            context?
+            get-context-scratch-dir
+            set-context-scratch-dir!
+            add-context-triggers!
+            register-context-var!
+            context-ref
+            resolve-context-ref
+            resolve-context-refs))
+
+(define-record-type <context>
+  (make-context)
+  context?
+  (scratch-dir get-context-scratch-dir set-context-scratch-dir!)
+  (vars get-context-vars set-context-vars!)
+  (triggers get-context-triggers set-context-triggers!))
+
+(define-record-type <context-ref>
+  (context-ref name)
+  context-ref?
+  (name var-name))
+
+(define (resolve-context-ref ctx v)
+  (if (context-ref? v)
+      (assoc-ref (get-context-vars ctx) (var-name v))
+      v))
+
+(define (resolve-context-refs ctx args)
+  (map (cut resolve-context-ref ctx <>) args))
+
+(define (add-context-triggers! ctx triggers)
+  (when triggers
+    (set-context-triggers! ctx (fold cons (or (get-context-triggers ctx) '()) triggers))))
+
+(define (register-context-var! ctx var-name val)
+  (set-context-vars! ctx (assoc-set! (get-context-vars ctx) var-name val)))