Ergo 0.9.0

This release is focused on overhauling error handling and improved error reporting.

But it also includes language and compiler changes: array index access, a new logging expression, support for compiler warnings and new built-in functions.

Note: While this release is backward compatible from a language perspective, it may require changes to application code which relies on the Ergo JavaScript API

Language

New expressions 🎁

• 🔢 Array index. You can now write e1[e2] to access the value of array e1 at (integer) index e2. This return an option for type safety. (#561)
• 📝 Logging. You can now write info(e1); e2 which indicate you want to print the value of e1 then evaluate e2. The semantic is defined as a no-op (so the compiler is free to optimise aggressively in some environments), but this can be useful when authoring template logic. This is an experimental feature, feedback is welcome (#121)

Built-in functions

• 📐 New length function returns the length of a string (#615)

Compiler

Errors 🐛

• 🎶 Errors use a new type hierarchy consistent with Composer Concerto!
• 📍 Better location information in type errors over built-in operators (#622)
• 🌷 Underlining errors does not look strange when tab characters are present (#626)
• 🌷Better type errors for missing fields (#629)

Warnings ⚠️

• New support for compiler warnings. You can turn warnings on by using the --warnings flag on ergoc ergorun or ergotop (#300)

Build 🏗

Dependencies Upgrades

• Switch to latest Q*cert library (1.3.0)