Project Lamdu

This project aims to create a "next-generation", "live programming" environment that radically improves the programming experience.

See the Main Page

Installation

osx

requires brew and git:

brew install ftgl leveldb haskell-stack
git clone --recursive https://github.com/lamdu/lamdu
cd lamdu
stack setup
stack install
~/.local/bin/lamdu

ubuntu

requires stack

sudo apt-get update -qq
sudo apt-get install git libftgl-dev libleveldb-dev libglfw-dev libxrandr-dev libxi-dev libxcursor-dev libxinerama-dev -yq
git clone --recursive https://github.com/lamdu/lamdu
cd lamdu
stack setup
stack install
~/.local/bin/lamdu

Tutorial

Simple expressions

At the top we have an interactive shell, where we can type calculations.

To type the calculation above:

• type "1+s"
• at this point we apply the addition operator to the number 1 and are picking the other argument to the addition. we are offered different options which contain the string "s" in their names
• pick the option we desire ("sqrt _") by filtering the option by typing and navigating to it with the cursor keys, and then pressing space (as of writing this, it is the first option offered, partly due to a currently minimal library of available functions).
• type "5" and press space
• select the whole expression by pressing shift+left twice
• type "/2" and press space

Directly under each expression in the code we see annotations of its evaluation results. Some annotations are more far apart from the expression's code due to its subexpression's annotation appearing between them.

So as to not expand the expression, some annotations are shrunk. In this case sqrt 5's annotation is shrunk. To see it in normal size - navigate to this expression, by going to the sqrt or 5 and pressing shift+left.

To name the golden ratio you have just declared, navigate to the top-level expression using repeated pressing of shift+left. Press 'x' to extract the code into a new definition. Type "golden" and return.

Creating a function

To create the function above:

• Navigate to the "New..." button and then press space
• type "fac x=x=0" and press space
• Select x == 0 by pressing shift+left
• Press ":" and press space to create a pattern-match on this boolean expression
• Type "1" and press space for the True branch
• Type "x*f x-1" and press space
• Final step to creating the function: Review its inferred type and press space to confirm it. Note that this step will be removed soon due to new design choices

We've now written the function. Let's use it.

• Go to the interactive shell (the top row in right of the ⋙ symbol), navigate to the top-level expression (repeatedly pressing shift+left if necessary) and then press delete to delete it.
• Type "fac 5" and press space

The function is now being evaluated and we see subexpression evaluation results within it. The result of x == 0 is displayed by a highlight on the active pattern match path (False).

This function is recursive and invoked additional calls to itself. To navigate between these calls go to the arrows under its parameter x and press right or left.

To rename any symbol, press return twice and edit the name. Note that all references are displayed with the updated name correctly.