Happy friday all, what’s the recommended way to debug errors like this : with-syntax: binding match failed in: (LINE-FUNC) The following clause is causing the error : (with-syntax* (.... [(LINE-FUNC) (format-id #'NUM "~a~a" "test" (syntax-e #'NUM))]))

[LINE-FUNC (format-id #'NUM "~a~a" "test" (syntax-e #'NUM)])

?

@soegaard2 that has too many () but is the right idea

Getting closer :slightly_smiling_face:

The return value of (format-id ...) is a single value, so the pattern to the left must be a single identifier.

The pattern (LINE-FUNC) matches a list of one element.

The error “binding match failed” says the pattern on the left didn’t match the value produced by the right hand side.

One way to debug is to print the result of the right hand side, and see if it returns what is expected.

Adding a couple of extra parenthesis there is easy to do - and can be hard to spot.

ah! fantastic!

Thanks for the answer and the debug tip

Hello. I am try to understand whats going wrong with a dynamic-require used outside of the REPL. I’ll describe details in a first message of this thread. Thanks in advance for the help

Here we have an example which works in REPL https://docs.racket-lang.org/reference/Module_Names_and_Loading.html?q=dynamic-require#%28def._%28%28quote._~23~25kernel%29._dynamic-require%29%29

> (module a racket/base (displayln "hello")) > (dynamic-require ''a #f) hello Same example is not working when running from the file(or via DrRacket “Run” button):

Welcome to fish, the friendly interactive shell /h/user λ echo '#lang racket (module a racket/base (displayln "hello")) (dynamic-require \'\'a #f)' > dynamic-require.rkt /h/user λ cat dynamic-require.rkt #lang racket (module a racket/base (displayln "hello")) (dynamic-require ''a #f) /h/user λ racket ./dynamic-require.rkt instantiate: unknown module module name: #<resolved-module-path:'a> context...: namespace-module-instantiate! "/home/user/dynamic-require.rkt": [running body] temp35_0 for-loop run-module-instance! perform-require! I think the reason for this is same as for eval (initial namespace is empty) https://docs.racket-lang.org/guide/eval.html#%28part._namespaces%29

This fails because the initial current namespace is empty. When you run racket in interactive mode (see Interactive Mode), the initial namespace is initialized with the exports of the racket module, but when you run a module directly, the initial namespace starts empty. But… I am expecting (module ...) to register in the current namespace’s registry.

1. Why is this happening? Does this have a simple explanation?
2. What modifications should be performed to dynamic-require example to make it work outside the REPL?

I think someone replied this to you already?

The solution is to follow https://lists.racket-lang.org/users/archive/2013-May/058029.html

Use quote-module-path

At the REPL, you are not in any module

But in a #lang file, you are

And (dynamic-require ''<something>) doesn’t work inside a module.

I am new to this slack channel. I have asked similar question in the github issues, but been redirected here.

Ok, it works with quote-module-path and your explanation makes sense. Thank you!