A defn.macro that creates bindings with generated names

[kiranandcode]

I'm trying to write a macro that generates additional bindings --- here's a simple example:

import:
     lib("racket/syntax.rkt") as racket

defn.macro 'variable $name $vl':
  def name_value : match name | '$(x :: Identifier)': to_string(x.unwrap())
  def gen_name : Syntax.make(racket.#{format-id}('$name', "~a_name", name_value)).relocate(name)
  'def $gen_name: $name_value
   def $name: $vl'

variable hello 10

hello_name

However, I can't seem to get the generated names to show up:

// hello_name: unbound identifier

[sorawee]

Can you show the full program that you ran? It makes sense that this errors, but I thought the error should be:

racket: undefined

or something along that line.

This program works for me:

#lang rhombus

import:
  rhombus/meta open

import:
  lib("racket/syntax.rkt"):
    meta
    as racket

defn.macro 'variable $name $vl':
  def name_value : match name | '$(x :: Identifier)': to_string(x.unwrap())
  def gen_name : Syntax.make(racket.#{format-id}('$name', "~a_name", name_value)).relocate(name)
  'def $gen_name: $name_value
   def $name: $vl'

variable hello 10

hello

[sorawee]

Sorry, I debugged by removing that _name and forgot to add it back.

(Edited: use Syntax.make)

Here's a version with _name:

#lang rhombus

import:
  rhombus/meta open

import:
  lib("racket/syntax.rkt"):
    meta
    as racket

defn.macro 'variable $name $vl':
  def name_stx: Syntax.make('$name')
  def gen_name : racket.#{format-id}(name_stx, "~a_name", name_stx)
  'def $gen_name: $vl
   def $name: $gen_name'

variable hello 10

hello_name
hello

[kiranandcode]

Hmm, that's strange --- the first snippet you posted doesn't work for me and has an undefined identifier, but the second one does work. I updated my rhombus installation this morning (raco pkg update http://github.com/racket/rhombus-prototype.git), so I should be running on the latest version.

looking into it, I guess the key change between the two versions is the Syntax.make of the stx object passed to format-id, as the following code works for me:

#lang rhombus

import:
  rhombus/meta open

import:
  lib("racket/syntax.rkt"):
    meta
    as racket

defn.macro 'variable $name $vl':
  def name_stx: Syntax.make('$name')
  def name_value : match name | '$(x :: Identifier)': to_string(x.unwrap())
  def gen_name : Syntax.make(racket.#{format-id}(name_stx, "~a_name", name_value)).relocate(name)
  'def $gen_name: $name_value
   def $name: $vl'

variable hello 10

[hello, hello_name]

Perfect, thanks!