cuddlefishie/natpl

Programming language / calculator for natural sciences

natpl's Issues

add a way to import other `.nat` files in the REPL and other files

This would allow more re-use of definitions.

Ideally for disambiguation also a namespacing mechansim should be present.

Maybe for "import everything" and "only import the name of the namespace" different statement types could be used?

• import OtherFile for loading OtherFile.nat from a set of known locations and then making all definitions usable
• use OtherFile for loading OtherFile.nat from a set of known locations and then allowing the use of definitions using OtherFile.some_name

add a way to display numbers as scientific, full or both

This could be done using a "meta switch" in the PEPL and maybe even be a command in itself in the language, so that user scripts (see #14) could set a default.

make span tracking more robust and add multi-line definitions

At the moment the parser only handles one line at a time and all spans are relative to that line.
When errors occur in a different file (see #15) then the proper error location should be tracked.

Handling multi-line definitions/expressions would also allow for more features later on, like if-else conditionals.

consider attaching units only to "atoms" and not composite values

The ValueKind/Unit split makes it so that elements in a vector all have to have the same unit.

In the long run having a way to support different units inside a vector (which would be more like tuples at that point then) might prove benefitial.

remove assertion item and allow variable redefinitions

Right now writing x = 5 has two meanings:

• if x is not yet defined it will be defined to the value 5
• if x is defined then it is asserted that x is equal to 5 and error if that's not the case

The assertion feature is very rarely used since the main usecase of natpl is in a REPL environment anyway.
This also means it's not possible to update the value of a variable.

---

It would be better to treat any <var> = <expr> item as a definition/value update. To implement that, the line item for disambiguation needs to be removed. Of course that requires small changes to the parser too.

natpl/natpl/src/syntax.rs

Line 87 in 602abff

MaybeDeclarationOrEqualityExpression(DeclarationOrEquality),

add an automatically loaded user-script to the REPL

This would allow users to create their own defaults for what is useful to them.

Similarly to the prelude, it would be automatically loaded on startup, but unlike the prelude could be changed by the users without recompiling the program.

Possible locations for the file:

• ~/.natpl/user_prelude.nat