Update demos and adds <|

demos/interactionTrees/environment.tri

@@ -0,0 +1,20 @@
+!import "../../lib/base.tri" !Local
+!import "../../lib/list.tri" !Local
+!import "../../lib/io.tri"   !Local
+
+-- Environment effects: ask and local.
+--   ask reads the current environment value.
+--   local f action runs action with the env transformed by f.
+--
+--   The CLI starts with an empty (Leaf) environment.  This demo uses
+--   local to inject a real string so that ask returns something readable.
+
+main = io <| 
+  (bind 
+  local (_ : "sandbox")
+    (bind ask (env :
+    bind (putStrLn (append "working in env: " env)) (_ :
+    pure "inside-done"))))
+  (outside :
+    bind (putStrLn (append "local returned: " outside)) (_ :
+    pure t))

demos/interactionTrees/forkAwait.tri

@@ -0,0 +1,18 @@
+!import "../../lib/base.tri" !Local
+!import "../../lib/list.tri" !Local
+!import "../../lib/io.tri"   !Local
+
+-- Basic fork and await.
+-- fork spawns a concurrent task and returns a handle.
+-- await blocks until the task completes and returns its value.
+
+worker = (msg :
+  bind (putStrLn (append "working: " msg)) (_ :
+  pure (append msg "-result")))
+
+main = io <|
+  (bind (fork (worker "job1")) (h1 :
+  bind (fork (worker "job2")) (h2 :
+  bind (await h1) (r1 :
+  bind (await h2) (r2 :
+  putStrLn (append "Got " (append r1 (append " and " r2))))))))

demos/interactionTrees/greet.tri

@@ -0,0 +1,10 @@
+!import "../../lib/base.tri" !Local
+!import "../../lib/list.tri" !Local
+!import "../../lib/io.tri"   !Local
+
+-- Greet and return a pure value.
+-- putStrLn writes to stdout; pure lifts "done" into IO.
+
+main = io (bind 
+  (putStrLn (append "Hello, " "tricu"))
+  (_ : pure ""))

demos/interactionTrees/safeRead.tri

@@ -0,0 +1,16 @@
+!import "../../lib/base.tri" !Local
+!import "../../lib/list.tri" !Local
+!import "../../lib/io.tri"   !Local
+
+-- readFile returns a Result.  matchResult branches on ok / err.
+-- Run with --allow-read PATH or --unsafe-io.
+
+safeRead = (path :
+  bind (readFile path)
+    (result :
+      matchResult
+        (err rest : pure "ERROR: Unable to read file")
+        (contents rest : pure contents)
+        result))
+
+main = io (safeRead "demos/interactionTrees/greet.tri")

demos/interactionTrees/shout.tri

@@ -0,0 +1,23 @@
+!import "../../lib/base.tri" !Local
+!import "../../lib/list.tri" !Local
+!import "../../lib/io.tri"   !Local
+
+-- Transform an IO result.
+--   mapIO applies a pure function to the value produced by an action.
+--   Run with --allow-read PATH or --unsafe-io.
+
+safeRead = (path :
+  bind (readFile path)
+    (result :
+      matchResult
+        (err rest : pure "missing")
+        (contents rest : pure contents)
+        result))
+
+shout = (path :
+  mapIO (safeRead path)
+    (text : append text "!!!"))
+
+main = io (bind 
+    (shout "demos/interactionTrees/greet.tri")
+    (text : putStrLn text))

demos/interactionTrees/state.tri

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+!import "../../lib/base.tri" !Local
+!import "../../lib/list.tri" !Local
+!import "../../lib/io.tri"   !Local
+
+-- Mutable state via get and put.
+--   get reads the current state.
+--   put replaces the state.
+--
+--   The CLI starts with an empty (Leaf) state.  This demo puts
+--   readable strings and prints them back out.
+
+main = io <|
+  bind (put "idle") (_ :
+  bind get (s1 :
+  bind (putStrLn (append "state: " s1)) (_ :
+  bind (put "running") (_ :
+  bind get (s2 :
+  bind (putStrLn (append "state: " s2)) (_ :
+  bind (put "done") (_ :
+  bind get (s3 :
+  bind (putStrLn (append "state: " s3)) (_ :
+  pure t)))))))))

demos/interactionTrees/writeThenRead.tri

@@ -0,0 +1,20 @@
+!import "../../lib/base.tri" !Local
+!import "../../lib/list.tri" !Local
+!import "../../lib/io.tri"   !Local
+
+-- Write a file, then read it back.
+--   thenIO discards the writeFile Result and continues.
+--   Run with --unsafe-io (needs both read and write permissions).
+
+writeThenRead = (path text :
+  thenIO
+    (writeFile path text)
+    (readFile path))
+
+main = io <|
+  (bind (writeThenRead "/tmp/tricu-demo.txt" "hello from tricu")
+    (result :
+      matchResult
+        (err rest : putStrLn "error")
+        (contents rest : putStrLn contents)
+        result))

demos/interactionTrees/yield.tri

@@ -0,0 +1,33 @@
+!import "../../lib/base.tri" !Local
+!import "../../lib/list.tri" !Local
+!import "../../lib/io.tri"   !Local
+
+-- Cooperative scheduling with yield.
+--   yield returns control to the scheduler so other tasks can run.
+--
+--   Two tasks print alternately because each yields after every line.
+
+--chatter = (name n :
+--  bind (putStrLn (append name " says 1")) (_ :
+--  bind yield (_ :
+--  bind (putStrLn (append name " says 2")) (_ :
+--  bind yield (_ :
+--  bind (putStrLn (append name " says 3")) (_ :
+--  pure n))))))
+
+chatter = name n : bind <|
+  putStrLn (append name " says 1") (_ :
+  bind yield (_ :
+  bind (putStrLn (append name " says 2")) (_ :
+  bind yield (_ :
+  bind (putStrLn (append name " says 3")) (_ :
+  pure n)))))
+
+
+main = io <|
+  bind (fork (chatter "A" "doneA")) (ha :
+  bind (fork (chatter "B" "doneB")) (hb :
+  bind yield (_ :
+  bind (await ha) (a :
+  bind (await hb) (b :
+  putStrLn (append "Finished: " (append a (append " " b))))))))