From 73381c3ad3405bfe2acd9a459a9b562ce89690f9 Mon Sep 17 00:00:00 2001
From: Sorawee Porncharoenwase <sorawee.pwase@gmail.com>
Date: Fri, 16 Apr 2021 16:55:55 +0700
Subject: [PATCH] expander: another improvement to make-readtable's error
 message

Currently `(make-readtable #f #\a 'dispatch-macro)` produces the error
message

```
; make-readtable: expected procedure argument after symbol argument
;   given: 'dispatch-macro
```

which is very confusing, because it sounds like `'dispatch-macro` is
incorrect, but it is in fact correct already.

This PR adjusts the error message to:

```
; make-readtable: expected procedure argument after symbol argument
;   symbol: 'dispatch-macro
```

which is the convention that is already used when the mode argument is not given.
---
 racket/src/bc/src/startup.inc          |  2 +-
 racket/src/cs/schemified/expander.scm  | 16 +++++++++-------
 racket/src/expander/read/readtable.rkt |  3 ++-
 3 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/racket/src/bc/src/startup.inc b/racket/src/bc/src/startup.inc
index 2ddf91363b..1f42bfc5a8 100644
--- a/racket/src/bc/src/startup.inc
+++ b/racket/src/bc/src/startup.inc
@@ -54518,7 +54518,7 @@ static const char *startup_source =
 "(if(char? mode_0)"
 "                                                                   \"expected readtable or #f argument after character argument\""
 "                                                                   \"expected procedure argument after symbol argument\")"
-"                                                                 \"given\""
+"                                                                 (if (char? mode_0) \"character\" \"symbol\")"
 " mode_0))"
 "(void))"
 "(values))))"
diff --git a/racket/src/cs/schemified/expander.scm b/racket/src/cs/schemified/expander.scm
index 829b6d760d..d09fcf6b69 100644
--- a/racket/src/cs/schemified/expander.scm
+++ b/racket/src/cs/schemified/expander.scm
@@ -61329,13 +61329,15 @@
                                   "expected 'non-terminating-macro after #f")))
                              (begin
                                (if (null? (cddr args_1))
-                                 (raise-arguments-error
-                                  'make-readtable
-                                  (if (char? mode_0)
-                                    "expected readtable or #f argument after character argument"
-                                    "expected procedure argument after symbol argument")
-                                  "given"
-                                  mode_0)
+                                 (let ((app_0
+                                        (if (char? mode_0)
+                                          "expected readtable or #f argument after character argument"
+                                          "expected procedure argument after symbol argument")))
+                                   (raise-arguments-error
+                                    'make-readtable
+                                    app_0
+                                    (if (char? mode_0) "character" "symbol")
+                                    mode_0))
                                  (void))
                                (let ((target_0 (caddr args_1)))
                                  (let ((rest-args_0 (cdddr args_1)))
diff --git a/racket/src/expander/read/readtable.rkt b/racket/src/expander/read/readtable.rkt
index b6cac3edfb..7661ad1755 100644
--- a/racket/src/expander/read/readtable.rkt
+++ b/racket/src/expander/read/readtable.rkt
@@ -81,7 +81,8 @@
                                (if (char? mode)
                                    "expected readtable or #f argument after character argument"
                                    "expected procedure argument after symbol argument")
-                               "given" mode))
+                               (if (char? mode) "character" "symbol")
+                               mode))
       (define target (caddr args))
       
       ;; Update the readtable