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Guide
The tour

The tour

A progressive walk through MWL. Each page introduces one layer of the language, builds on the pages before it, and ends with pointers into the Reference for the precise semantics. Read in order if you are new; each page also stands alone well enough to refresh one topic.

In this section

  • Your first Flow — The smallest complete workflow: Steps, a Call, and a Return.
  • Data and expressions — How values move between Steps, and how {{ ... }} expressions shape them.
  • Branching and variables — Routing with Match, carrying values with vars, and configuring a Flow with parameters.
  • Calls and Results — The call object in full: targets, with versus input, the arms, and the Result every call yields.
  • Handling failures — The failure envelope, catch routing, the failure context, and Raise.
  • Subflows — Named and inline Flows, parameter passing, isolation, and what calling a Flow shares with calling a provider.
  • Concurrency with Gather — Fan-out in two forms, completion policies, and the collected Results.
  • Middleware — Wrapping dispatches and Flows with retry, timeout, looping, cleanup, and platform behaviors.