tricu

An interpreted language for exploring Tree Calculus
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environment.tri (587B)

      1 !import "prelude" !Local
      2 !import "io"      !Local
      3 
      4 -- Environment effects: ask and local.
      5 --   ask reads the current environment value.
      6 --   local f action runs action with the env transformed by f.
      7 --
      8 --   The CLI starts with an empty (Leaf) environment.  This demo uses
      9 --   local to inject a real string so that ask returns something readable.
     10 
     11 main = io <| 
     12   (bind 
     13   local (_ : "sandbox")
     14     (bind ask (env :
     15     bind (putStrLn (append "working in env: " env)) (_ :
     16     pure "inside-done"))))
     17   (outside :
     18     bind (putStrLn (append "local returned: " outside)) (_ :
     19     pure t))