This tutorial will guide you in developing Michelson contracts using Indigo. It will present the features of the language and provide some examples as well.
On the software side you will need to install stack for compilation and grab the source code for Indigo:
git clone https://gitlab.com/morley-framework/morley.git cd morley
All the resources for this tutorial, including this documentation and the
examples' source code, are located in the
Setup recommendations and first steps¶
If you are not a Haskell developer and have no intention of becoming one, you should still be able to follow the tutorial with its examples and write your own contracts as well.
We can start by opening up an interactive shell with Indigo loaded in it.
Cleaner REPL prompt
Before opening the shell you are advised to modify the prompt, as the
standard one contains a lot of text. To use a simple one you can simply copy
.ghci file to your home directory:
:set prompt "\ESC[32m>> \ESC[m" :set prompt-cont ">| "
Provided that you have installed
stack you can open a REPL by issuing, from
the root directory of the cloned repository:
stack ghci :indigo-repl
It will take some time to compile everything the first time around, but it will get faster later on, I promise.
You can now load a source file by using the
:load command, we can start by
loading the example code provided in this chapter:
module Indigo.Tutorial.GettingStarted.Example ( exampleContract ) where import Indigo exampleContract :: IndigoContract Integer Integer exampleContract param = defContract do a <- new$ 1 int storageVar =: param + a
For these examples, you may receive warnings about
you can safely ignore these.
Now you have access to the contracts exported by this module (the ones on the
list at the top of the file), that in this case is just
We'll go through what is the syntax of Indigo, but if you take a quick look at
exampleContract you should be able to see that it implements a simple contract
that takes an
Integer parameter, creates a new variable
a of value
finally sets its storage with the sum of
a. Very simple.
You can compile it and see what's the Michelson code for this (or any other) Indigo contract by using:
printAsMichelson @Integer @Integer exampleContract
or save it to a file with:
saveAsMichelson @Integer @Integer exampleContract "<path-to-file>.tz"
that you can run and deploy on the network!
Note that it is necessary for both to specify the parameter and storage types
(in this order), that in this case are just
With these tools at your disposal you will be able to create Indigo contracts and compile them to Michelson, just by using the REPL.
If you are ready for it, you should head straight for the next chapter: Basics and Variables.
Technical details: developing using Indigo¶
If you are a Haskell developer interested in developing your own library/contract using Indigo, you'll probably be better off following this tutorial (that will contain more of these technical paragraphs) and checking the Haddock documentation as well.
Generate Haddock documentation
You can generate Haddock documentation for indigo from its folder
, by using:
To be able to write your own project you'll probably just need to
in your modules and pay attention to enabling the right language extensions.
You may not need all of them, but some are necessary and allow the language to
be neatly usable, for example
RebindableSyntax is what makes it possible to use
the do-notation and Haskell's standard
if ... then ... else statements (more
details on this will come later).