Implement format string

[gekkowrld]

The formatting follows the following style:
andika("") // nothing
andika() // newline (historical reasons)
andika("hello") // hello
andika("mimi ni {0} niko hapa {1} kama {0}", "Nuru", "github")
// mimi ni Nuru niko hapa github kama Nuru
andika("{0}") // error
andika("", "") // error

The errors are still generic with no helpful information.
This is not an issue with this pr only but deeper so future problem.

This is potentially solves #81
and successor to #82

Actually does "Should have string manipulation instead" #82 (comment)

[AvicennaJr]

Here are my thoughts:

1. andika("mimi ni {0} niko hapa {1} kama {0}", "Nuru", "github") will break the syntax of how Nuru currently works:

2. What if someone wanted to print {0}? Since { and } are not escape characters this is not possible.
3. There is no reason for andika("", "") to throw an error

My advice would be to add string formatting to the string object itself, I've included examples in Go and Python:

1. Python:

2. Go:

[gekkowrld]

andika("mimi ni {0} niko hapa {1} kama {0}", "Nuru", "github") will break the syntax of how Nuru currently works:

True but not many programs will be affected.

What if someone wanted to print {0}? Since { and } are not escape characters this is not possible.

Fixed in comit f49a4b7

There is no reason for andika("", "") to throw an error

This is an invalid syntax, Go (the golps lsp atleast) throws a warning and go itself prints "%!(EXTRA string=)".
This is done on the Printf, but println works just fine.

My advice would be to add string formatting to the string object itself, I've included examples in Go and Python:

Python does have that only on fstring, the .format just iterates over the string object mutating as it goes by.
Look at https://github.com/python/cpython/blob/main/Lib/string.py for .format()
Look at https://docs.python.org/3/reference/lexical_analysis.html#f-strings for fstrings (they are baked into the lexical stage)
Lexing fstring starts here https://github.com/python/cpython/blob/main/Parser/lexer/lexer.c#L1063

Go doesn't have string object, because a string is just a sequence of bytes to it.
The formatting is done by Printf and Sprintf (f for formatting), all the others like Println, Print and so on
will just ignore the '%s' syntax as its not a special token in go itself but an added on by the stdlib

Look at the '%' formatting here https://github.com/golang/go/blob/master/src/fmt/print.go
and the whole module for other things like '%#'... https://github.com/golang/go/blob/master/src/fmt

[AvicennaJr]

Python does have that only on fstring, the .format just iterates over the string object mutating as it goes by.
Look at https://github.com/python/cpython/blob/main/Lib/string.py for .format()

So the equivalent in Nuru would be to do it on the String object, and not the built-in andika function right?

[AvicennaJr]

Consider a case where someone wants to format a string and assign it to a variable, how would one achieve that with your implementation?

[gekkowrld]

So the equivalent in Nuru would be to do it on the String object, and not the built-in andika function right?

Yes, so something like "Jina ni {0}\n".unda("Nuru").

This will mean that the andika() function can be used as before.

[gekkowrld]

Consider a case where someone wants to format a string and assign it to a variable, how would one achieve that with your implementation?

We could have added another function for formatting e.g unda() and then by default call it for formatting and print the resulting string, like your example in golang Sprintf

[AvicennaJr]

Yes, so something like "Jina ni {0}\n".unda("Nuru").

Yep, but probably a different name (don't wanna confuse people with unda).

This will mean that the andika() function can be used as before.

Exactly

We could have added another function for formatting e.g unda() and then by default call it for formatting and print the resulting string, like your example in golang Sprintf

This will add unnecessary complexity. Let's go with modifying the String object. If you agree, kindly close this PR and make a new one.

[gekkowrld]

Yep, but probably a different name (don't wanna confuse people with unda).

What other name conveys that it will be formatting without confusion?

[AvicennaJr]

What other name conveys that it will be formatting without confusion?

Not sure 😅

[gekkowrld]

I'll just use unda until a better name is found.
Will close this one once i open another pr

[gekkowrld]

Look at: #94