freja-eval-last-expr

Alternative evaluate last expression support for the freja editor.

Prerequisites

The freja editor.

Setup

0. Clone this repository somewhere and cd to the resulting directory
1. Start freja with: freja ./freja-eval-last-expr/defaults.janet
2. Control+L to load the file

Example Usage

1. In freja's buffer window, type some code that could be evaluated successfully, e.g.:

   (+ 1 1)
   

2. With the cursor after the closing paren, press the key sequence Control+Enter.

3. Observe in the console or the echoer area at the bottom of freja's window, the following sort of output:

   => (+ 1 1)
   2
   

Explanation

In this version, Control+Enter invokes the function eval-last-expr which:

• Determines a region of text containing (but not necessarily limited to) the expression immediately preceding the cursor
• Analyzes the region to determine a "last expression"
• Hands the determined expression off for evaluation

Note that the code relies on a Left Margin Convention for Janet code. Briefly, this means that in one's Janet code the presence of a left paren, single quote, or a tilde in the left-most column always indicates the beginning of a top-level form.

Tests

There are tests than can be run by jpm test.

One set of tests runs tests inside freja while the other uses janet-usages-as-tests to test supporting code.