From 8dea96894b6965189bfb873fbf24751c2e440935 Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Fri, 6 May 2016 10:34:43 -0700
Subject: [PATCH 01/13] add dependency

---
 brag/info.rkt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/brag/info.rkt b/brag/info.rkt
index 45a38e2..810a1d4 100755
--- a/brag/info.rkt
+++ b/brag/info.rkt
@@ -1,6 +1,6 @@
 #lang setup/infotab
 
-(define deps '("base" "parser-tools-lib" "rackunit-lib" "python-tokenizer"))
+(define deps '("base" "beautiful-racket-lib" "parser-tools-lib" "rackunit-lib" "python-tokenizer"))
 (define build-deps '("at-exp-lib" "parser-tools-doc" "racket-doc"
                      "scribble-lib"))
 (define collection 'multi)

From f072c9f808e1cd39e6895c6355bf93d6d3250b28 Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Fri, 6 May 2016 10:55:04 -0700
Subject: [PATCH 02/13] angle-hiding in parser

---
 beautiful-racket/br/demo/txtadv/expander.rkt | 20 ++++++++------------
 beautiful-racket/br/demo/txtadv/parser.rkt   | 18 +++++++++---------
 2 files changed, 17 insertions(+), 21 deletions(-)

diff --git a/beautiful-racket/br/demo/txtadv/expander.rkt b/beautiful-racket/br/demo/txtadv/expander.rkt
index af11bf1..2c64400 100644
--- a/beautiful-racket/br/demo/txtadv/expander.rkt
+++ b/beautiful-racket/br/demo/txtadv/expander.rkt
@@ -35,7 +35,7 @@
   #'(module-begin _section ...))
 
 (provide verb-section)
-(define-inverting #'(verb-section _heading _verb-item ...)
+(define-inverting #'(verb-section _verb-item ...)
   (inject-syntax ([#'in-verbs (shared-syntax 'in-verbs)])
                  #'(define-verbs in-verbs
                      _verb-item ...)))
@@ -47,14 +47,11 @@
 
 (provide verb-name)
 (define-cases #'verb-name
-  ;; cases with literals go first, so they're not caught by wildcards
-  [#'(_ "," _id) #'(_id #f)]
-  [#'(_ "," _id _underscore) #'(_id #t)]
   [#'(_ _id) #'(_id #f)]
   [#'(_ _id _underscore) #'(_id #t)])
 
 (provide everywhere-section)
-(define-inverting #'(everywhere-section _heading [_name _desc] ...)
+(define-inverting #'(everywhere-section [_name _desc] ...)
   #'(define-everywhere everywhere-actions
       ([_name _desc] ...)))
 
@@ -63,7 +60,7 @@
   #'(_id _desc))
 
 (provide things-section)
-(define-inverting #'(things-section _heading _thing ...)
+(define-inverting #'(things-section _thing ...)
   #'(begin _thing ...))
 
 (provide thing-item)
@@ -71,7 +68,7 @@
   #'(define-thing _thingname [_actionname _actiondesc] ...))
 
 (provide places-section)
-(define-inverting #'(places-section _heading _placeitem ...)
+(define-inverting #'(places-section _placeitem ...)
   #'(begin _placeitem ...))
 
 (provide place-item)
@@ -82,18 +79,17 @@
 (define #'(place-descrip _desc) #'_desc)
 
 (provide place-items)
-(define-inverting #'(place-items "[" _id ... "]") #'(_id ...))
+(define-inverting #'(place-items _id ...) #'(_id ...))
 
 (provide place-name)
 (define-cases #'place-name
-  [#'(_ "," _id) #'_id]
   [#'(_ _id) #'_id])
 
 
 (provide s-exp)
 (define-cases-inverting #'s-exp
-  [#'(_ "(" _sx ... ")") #'(_sx ...)]
-  [#'(_ _sx) #'_sx])
+  [#'(_ _sx) #'_sx]
+  [#'(_ _sx ... ) #'(_sx ...)])
 
 
 ;; todo: consolidate the game-starters.
@@ -107,7 +103,7 @@
                               everywhere-actions)))
 
 (provide start-section)
-(define #'(start-section _heading _where)
+(define #'(start-section _where)
   (inject-syntax ([#'in-verbs (shared-syntax 'in-verbs)])
                  #'(init-game _where
                               in-verbs
diff --git a/beautiful-racket/br/demo/txtadv/parser.rkt b/beautiful-racket/br/demo/txtadv/parser.rkt
index afa8e0f..9a0798c 100644
--- a/beautiful-racket/br/demo/txtadv/parser.rkt
+++ b/beautiful-racket/br/demo/txtadv/parser.rkt
@@ -2,30 +2,30 @@
 
 txtadv-program : verb-section everywhere-section things-section places-section start-section
 
-verb-section : "===VERBS===" verb-item+
+verb-section : <"===VERBS==="> verb-item+
 
 verb-item : verb-name+ s-exp
 
-verb-name : [","] ID ["_"]
+verb-name : [<",">] ID ["_"]
 
-everywhere-section : "===EVERYWHERE===" id-desc+
+everywhere-section : <"===EVERYWHERE==="> id-desc+
 
-things-section : "===THINGS===" thing-item+
+things-section : <"===THINGS==="> thing-item+
 
 thing-item : DASHED-NAME id-desc+
 
-places-section : "===PLACES===" place-item+
+places-section : <"===PLACES==="> place-item+
 
 place-item : DASHED-NAME place-descrip place-items id-desc+
 
 place-descrip : STRING ; `place-desc` is already used in expander
 
-place-items : "[" place-name* "]" ; `place-things` is already used
+place-items : <"["> place-name* <"]"> ; `place-things` is already used
 
-place-name : [","] ID
+place-name : [<",">] ID
 
-start-section : "===START===" place-name
+start-section : <"===START==="> place-name
 
 id-desc : ID s-exp
 
-s-exp : ID | STRING | "(" s-exp* ")"
\ No newline at end of file
+s-exp : ID | STRING | <"("> s-exp* <")">
\ No newline at end of file

From 2026c603de63cb04bcc8449d484b6457956b9910 Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Fri, 6 May 2016 12:36:25 -0700
Subject: [PATCH 03/13] make ids hideable

---
 brag/brag/codegen/codegen.rkt             | 52 +++++++++++------------
 brag/brag/codegen/runtime.rkt             | 14 +++---
 brag/brag/elider/json-elider-toy.rkt      |  4 +-
 brag/brag/elider/json-elider.rkt          |  2 +-
 brag/brag/elider/test-json-elider-toy.rkt |  9 ++++
 brag/brag/elider/test-json-elider.rkt     |  4 +-
 6 files changed, 45 insertions(+), 40 deletions(-)
 create mode 100644 brag/brag/elider/test-json-elider-toy.rkt

diff --git a/brag/brag/codegen/codegen.rkt b/brag/brag/codegen/codegen.rkt
index 2b91fd3..c459fe1 100755
--- a/brag/brag/codegen/codegen.rkt
+++ b/brag/brag/codegen/codegen.rkt
@@ -43,8 +43,8 @@
        MB: `rules` still carries 'hide syntax property
        |#
        #;(report flattened-rules)
-
-
+       
+       
        #|
        MB: `flattened-rules` still carries 'hide syntax property
        |#
@@ -52,7 +52,7 @@
        #;(report flattened-rules)
        
        (define generated-rule-codes (map flat-rule->yacc-rule flattened-rules))
-
+       
        #|
        MB: `generated-rule-codes` loses the 'hide syntax property
        |#
@@ -216,29 +216,29 @@
     (for/list ([translated-pattern (in-list translated-patterns)]
                [primitive-pattern (syntax->list a-clause)]
                [pos (in-naturals 1)])
-              (with-syntax ([$X 
-                             (format-id translated-pattern "$~a" pos)]
-                            [$X-start-pos 
-                             (format-id translated-pattern "$~a-start-pos" pos)]
-                            [$X-end-pos
-                             (format-id translated-pattern "$~a-end-pos" pos)])
-                (syntax-case primitive-pattern (id lit token inferred-id)
-                  
-                  ;; When a rule usage is inferred, the value of $X is a syntax object
-                  ;; whose head is the name of the inferred rule . We strip that out,
-                  ;; leaving the residue to be absorbed.
-                  [(inferred-id val reason)
-                   #'(syntax-case $X ()
-                       [(inferred-rule-name . rest)
-                        (syntax->list #'rest)])]
-                  [(id val)
-                   #'(list $X)]
-                  ;; move the 'hide syntax property into the translated-action
-                  ;; because syntax gets datum-ized
-                  [(lit val)
-                   #`(list (atomic-datum->syntax $X $X-start-pos $X-end-pos #,(syntax-property primitive-pattern 'hide)))]
-                  [(token val)
-                   #`(list (atomic-datum->syntax $X $X-start-pos $X-end-pos #,(syntax-property primitive-pattern 'hide)))]))))
+              (if (syntax-property primitive-pattern 'hide)
+                  #'null
+                  (with-syntax ([$X 
+                                 (format-id translated-pattern "$~a" pos)]
+                                [$X-start-pos 
+                                 (format-id translated-pattern "$~a-start-pos" pos)]
+                                [$X-end-pos
+                                 (format-id translated-pattern "$~a-end-pos" pos)])
+                    (syntax-case primitive-pattern (id lit token inferred-id)
+                      
+                      ;; When a rule usage is inferred, the value of $X is a syntax object
+                      ;; whose head is the name of the inferred rule . We strip that out,
+                      ;; leaving the residue to be absorbed.
+                      [(inferred-id val reason)
+                       #'(syntax-case $X ()
+                           [(inferred-rule-name . rest)
+                            (syntax->list #'rest)])]
+                      [(id val)
+                       #'(list $X)]
+                      [(lit val)
+                       #'(list (atomic-datum->syntax $X $X-start-pos $X-end-pos))]
+                      [(token val)
+                       #'(list (atomic-datum->syntax $X $X-start-pos $X-end-pos))])))))
   
   (define whole-rule-loc
     (if (empty? translated-patterns)
diff --git a/brag/brag/codegen/runtime.rkt b/brag/brag/codegen/runtime.rkt
index eb220da..03eed87 100755
--- a/brag/brag/codegen/runtime.rkt
+++ b/brag/brag/codegen/runtime.rkt
@@ -150,15 +150,12 @@ This would be the place to check a syntax property for hiding.
 (define stx-with-original?-property
   (read-syntax #f (open-input-string "meaningless-string")))
 
-(define elided (gensym))
 
 ;; atomic-datum->syntax: datum position position
 ;; Helper that does the ugly work in wrapping a datum into a syntax
 ;; with source location.
-(define (atomic-datum->syntax d start-pos end-pos [hide? #f])
-  (if hide?
-      elided
-      (datum->syntax #f d (positions->srcloc start-pos end-pos) stx-with-original?-property)))
+(define (atomic-datum->syntax d start-pos end-pos)
+  (datum->syntax #f d (positions->srcloc start-pos end-pos) stx-with-original?-property))
 
 
 
@@ -166,10 +163,9 @@ This would be the place to check a syntax property for hiding.
 ;; Creates an stx out of the rule name and its components.
 ;; The location information of the rule spans that of its components.
 (define (rule-components->syntax rule-name/false #:srcloc [srcloc #f] . components)
-  (define flattened-elided-components (filter-not (λ(c) (eq? c elided)) (apply append components)))
   (datum->syntax #f 
                  (cons
-                        (datum->syntax #f rule-name/false srcloc stx-with-original?-property)
-                        flattened-elided-components)
+                  (datum->syntax #f rule-name/false srcloc stx-with-original?-property)
+                  (apply append components))
                  srcloc
-                 stx-with-original?-property))
+                 stx-with-original?-property))
\ No newline at end of file
diff --git a/brag/brag/elider/json-elider-toy.rkt b/brag/brag/elider/json-elider-toy.rkt
index 3d55a38..8eed9e8 100644
--- a/brag/brag/elider/json-elider-toy.rkt
+++ b/brag/brag/elider/json-elider-toy.rkt
@@ -1,4 +1,4 @@
 #lang brag
 
-;; Simple baby example of JSON structure
-json: ID <":"> ID
+thing : foo
+foo : <"bar">
diff --git a/brag/brag/elider/json-elider.rkt b/brag/brag/elider/json-elider.rkt
index 224acd4..cdebc9e 100755
--- a/brag/brag/elider/json-elider.rkt
+++ b/brag/brag/elider/json-elider.rkt
@@ -14,4 +14,4 @@ array: "[" [json ("," json)*] "]"
 
 object: <"{"> [kvpair ("," kvpair)*] <"}">
 
-kvpair: <ID> <":"> json
+kvpair: <ID> ":" <json>
diff --git a/brag/brag/elider/test-json-elider-toy.rkt b/brag/brag/elider/test-json-elider-toy.rkt
new file mode 100644
index 0000000..c3072c3
--- /dev/null
+++ b/brag/brag/elider/test-json-elider-toy.rkt
@@ -0,0 +1,9 @@
+#lang br
+(require "json-elider-toy.rkt"
+         brag/support
+         rackunit)
+
+(check-equal?
+ (syntax->datum
+  (parse (list "bar")))
+ '(thing))
diff --git a/brag/brag/elider/test-json-elider.rkt b/brag/brag/elider/test-json-elider.rkt
index bbb7e4d..89287ed 100755
--- a/brag/brag/elider/test-json-elider.rkt
+++ b/brag/brag/elider/test-json-elider.rkt
@@ -10,10 +10,10 @@
                ":"
                (token 'STRING "'hello world'")
                "}")))
- '(json (object (kvpair (json (string "'hello world'"))))))
+ '(json (object (kvpair "message" (json (string "'hello world'"))))))
 
 
-(check-equal? 
+#;(check-equal? 
  (syntax->datum
   (parse "[[[{}]],[],[[{}]]]"))
  '(json (array #\[ (json (array #\[ (json (array #\[ (json (object)) #\])) #\])) #\, (json (array #\[ #\])) #\, (json (array #\[ (json (array #\[ (json (object )) #\])) #\])) #\])))

From 6d801934193ed77be651b61f02562889c2b1bd12 Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Fri, 6 May 2016 12:58:15 -0700
Subject: [PATCH 04/13] lhs-id modifications ; tests pass

---
 brag/brag/rules/lexer.rkt  |  5 ++---
 brag/brag/rules/parser.rkt | 20 +++++++++++++++++++-
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/brag/brag/rules/lexer.rkt b/brag/brag/rules/lexer.rkt
index 877f563..32a205f 100755
--- a/brag/brag/rules/lexer.rkt
+++ b/brag/brag/rules/lexer.rkt
@@ -22,9 +22,6 @@
       (:+ id-char)))
 
 
-
-
-
 (define lex/1
   (lexer-src-pos
    [(:: "'"
@@ -64,6 +61,8 @@
     (token-EOF lexeme)]
    [(:: id (:* whitespace) ":")
     (token-RULE_HEAD lexeme)]
+   [(:: "<" id ">" (:* whitespace) ":")
+    (token-RULE_HEAD_HIDDEN lexeme)]
    [id
     (token-ID lexeme)]
    
diff --git a/brag/brag/rules/parser.rkt b/brag/brag/rules/parser.rkt
index a9dc02d..5a318dc 100755
--- a/brag/brag/rules/parser.rkt
+++ b/brag/brag/rules/parser.rkt
@@ -17,6 +17,7 @@
          token-PIPE
          token-REPEAT
          token-RULE_HEAD
+         token-RULE_HEAD_HIDDEN
          token-ID
          token-LIT
          token-EOF
@@ -45,6 +46,7 @@
                        PIPE
                        REPEAT
                        RULE_HEAD
+                       RULE_HEAD_HIDDEN
                        ID
                        LIT
                        EOF))
@@ -84,7 +86,23 @@
                            (position-col $1-start-pos))
                       trimmed
                       #f)
-              $2))]]
+              $2))]
+     
+     ;; angles indicate hiding. set hide value to #t
+     [(RULE_HEAD_HIDDEN pattern)
+      (begin
+        (begin 
+        (define trimmed (cadr (regexp-match #px"<(\\w+)>\\s*:$" $1)))
+        (rule (position->pos $1-start-pos)
+              (position->pos $2-end-pos)
+              (lhs-id (position->pos $1-start-pos)
+                      (pos (+ (position-offset $1-start-pos)
+                              (string-length trimmed))
+                           (position-line $1-start-pos)
+                           (position-col $1-start-pos))
+                      trimmed
+                      #t)
+              $2)))]]
     
     [pattern
      [(implicit-pattern-sequence PIPE pattern)

From f6181b90d72250cca79353bc406a3b53a1feb9d2 Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Fri, 6 May 2016 13:22:38 -0700
Subject: [PATCH 05/13] lhs-id splicing works ; tests pass

---
 brag/brag/codegen/codegen.rkt         |  8 +++++---
 brag/brag/codegen/runtime.rkt         | 22 ++++++++++++++--------
 brag/brag/elider/json-elider.rkt      |  2 +-
 brag/brag/elider/test-json-elider.rkt |  4 ++--
 brag/brag/rules/stx.rkt               | 24 +++++++++++++-----------
 5 files changed, 35 insertions(+), 25 deletions(-)

diff --git a/brag/brag/codegen/codegen.rkt b/brag/brag/codegen/codegen.rkt
index c459fe1..f8ec6dc 100755
--- a/brag/brag/codegen/codegen.rkt
+++ b/brag/brag/codegen/codegen.rkt
@@ -42,7 +42,7 @@
        #|
        MB: `rules` still carries 'hide syntax property
        |#
-       #;(report flattened-rules)
+       #;(report rules)
        
        
        #|
@@ -54,7 +54,7 @@
        (define generated-rule-codes (map flat-rule->yacc-rule flattened-rules))
        
        #|
-       MB: `generated-rule-codes` loses the 'hide syntax property
+       MB: `generated-rule-codes` loses the 'hide syntax property (but not for lhs-ids)
        |#
        #;(report generated-rule-codes)
        
@@ -179,6 +179,7 @@
 ;;     stx :== (name (U tokens rule-stx) ...)
 ;;
 (define (flat-rule->yacc-rule a-flat-rule)
+  ;; lhs-ids still carry 'hide property on #'name field
   #;(report a-flat-rule)
   (syntax-case a-flat-rule ()
     [(rule-type origin name clauses ...)
@@ -251,7 +252,8 @@
                 [(translated-action ...) translated-actions])
     #`[(translated-pattern ...)
        (rule-components->syntax '#,rule-name/false translated-action ...
-                                #:srcloc #,whole-rule-loc)]))
+                                #:srcloc #,whole-rule-loc
+                                #:splice? #,(syntax-property rule-name/false 'hide))]))
 
 
 
diff --git a/brag/brag/codegen/runtime.rkt b/brag/brag/codegen/runtime.rkt
index 03eed87..ebb8902 100755
--- a/brag/brag/codegen/runtime.rkt
+++ b/brag/brag/codegen/runtime.rkt
@@ -158,14 +158,20 @@ This would be the place to check a syntax property for hiding.
   (datum->syntax #f d (positions->srcloc start-pos end-pos) stx-with-original?-property))
 
 
-
+(define splice-signal '@)
 ;; rule-components->syntax: (U symbol false) (listof stx) ... #:srcloc (U #f (list src line column offset span)) -> stx
 ;; Creates an stx out of the rule name and its components.
 ;; The location information of the rule spans that of its components.
-(define (rule-components->syntax rule-name/false #:srcloc [srcloc #f] . components)
-  (datum->syntax #f 
-                 (cons
-                  (datum->syntax #f rule-name/false srcloc stx-with-original?-property)
-                  (apply append components))
-                 srcloc
-                 stx-with-original?-property))
\ No newline at end of file
+(define (rule-components->syntax rule-name/false #:srcloc [srcloc #f] #:splice? [splice #f] . componentss)
+  (let ([componentss (append-map (λ(cs)
+                                   (if (and (pair? cs) (syntax-property (car cs) 'splice))
+                                            (list (cdr (syntax->list (car cs))))
+                                            (list cs))) componentss)])
+    (syntax-property
+     (datum->syntax #f 
+                    (cons
+                     (datum->syntax #f rule-name/false srcloc stx-with-original?-property)
+                     (apply append componentss))
+                    srcloc
+                    stx-with-original?-property)
+     'splice splice)))
\ No newline at end of file
diff --git a/brag/brag/elider/json-elider.rkt b/brag/brag/elider/json-elider.rkt
index cdebc9e..677a02d 100755
--- a/brag/brag/elider/json-elider.rkt
+++ b/brag/brag/elider/json-elider.rkt
@@ -14,4 +14,4 @@ array: "[" [json ("," json)*] "]"
 
 object: <"{"> [kvpair ("," kvpair)*] <"}">
 
-kvpair: <ID> ":" <json>
+<kvpair> : <ID> ":" <json>
diff --git a/brag/brag/elider/test-json-elider.rkt b/brag/brag/elider/test-json-elider.rkt
index 89287ed..c7e48d0 100755
--- a/brag/brag/elider/test-json-elider.rkt
+++ b/brag/brag/elider/test-json-elider.rkt
@@ -10,10 +10,10 @@
                ":"
                (token 'STRING "'hello world'")
                "}")))
- '(json (object (kvpair "message" (json (string "'hello world'"))))))
+ '(json (object ":")))
 
 
-#;(check-equal? 
+(check-equal? 
  (syntax->datum
   (parse "[[[{}]],[],[[{}]]]"))
  '(json (array #\[ (json (array #\[ (json (array #\[ (json (object)) #\])) #\])) #\, (json (array #\[ #\])) #\, (json (array #\[ (json (array #\[ (json (object )) #\])) #\])) #\])))
diff --git a/brag/brag/rules/stx.rkt b/brag/brag/rules/stx.rkt
index 0317fcf..80197b5 100755
--- a/brag/brag/rules/stx.rkt
+++ b/brag/brag/rules/stx.rkt
@@ -21,17 +21,19 @@
 
 (define (rule->stx source a-rule)
   (define id-stx
-    (datum->syntax #f
-                   (string->symbol (lhs-id-val (rule-lhs a-rule)))
-                   (list source
-                         (pos-line (lhs-id-start (rule-lhs a-rule)))
-                         (pos-col (lhs-id-start (rule-lhs a-rule)))
-                         (pos-offset (lhs-id-start (rule-lhs a-rule)))
-                         (if (and (number? (pos-offset (lhs-id-start (rule-lhs a-rule))))
-                                  (number? (pos-offset (lhs-id-end (rule-lhs a-rule)))))
-                             (- (pos-offset (lhs-id-end (rule-lhs a-rule)))
-                                (pos-offset (lhs-id-start (rule-lhs a-rule))))
-                             #f))))
+    (syntax-property
+     (datum->syntax #f
+                    (string->symbol (lhs-id-val (rule-lhs a-rule)))
+                    (list source
+                          (pos-line (lhs-id-start (rule-lhs a-rule)))
+                          (pos-col (lhs-id-start (rule-lhs a-rule)))
+                          (pos-offset (lhs-id-start (rule-lhs a-rule)))
+                          (if (and (number? (pos-offset (lhs-id-start (rule-lhs a-rule))))
+                                   (number? (pos-offset (lhs-id-end (rule-lhs a-rule)))))
+                              (- (pos-offset (lhs-id-end (rule-lhs a-rule)))
+                                 (pos-offset (lhs-id-start (rule-lhs a-rule))))
+                              #f)))
+     'hide (lhs-id-hide (rule-lhs a-rule))))
   (define pattern-stx (pattern->stx source (rule-pattern a-rule)))
   (define line (pos-line (rule-start a-rule)))
   (define column (pos-col (rule-start a-rule)))

From 992fccdb1d6cf3f998e0faaaff7f536aa2869d39 Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Fri, 6 May 2016 13:24:15 -0700
Subject: [PATCH 06/13] change lhs-id key from 'hide to 'splice

---
 brag/brag/codegen/codegen.rkt    | 6 +++---
 brag/brag/rules/rule-structs.rkt | 2 +-
 brag/brag/rules/stx.rkt          | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/brag/brag/codegen/codegen.rkt b/brag/brag/codegen/codegen.rkt
index f8ec6dc..b58f8df 100755
--- a/brag/brag/codegen/codegen.rkt
+++ b/brag/brag/codegen/codegen.rkt
@@ -54,7 +54,7 @@
        (define generated-rule-codes (map flat-rule->yacc-rule flattened-rules))
        
        #|
-       MB: `generated-rule-codes` loses the 'hide syntax property (but not for lhs-ids)
+       MB: `generated-rule-codes` loses the 'hide syntax property (but lhs-ids carry 'splice)
        |#
        #;(report generated-rule-codes)
        
@@ -179,7 +179,7 @@
 ;;     stx :== (name (U tokens rule-stx) ...)
 ;;
 (define (flat-rule->yacc-rule a-flat-rule)
-  ;; lhs-ids still carry 'hide property on #'name field
+  ;; lhs-ids still carry 'splice property on #'name field
   #;(report a-flat-rule)
   (syntax-case a-flat-rule ()
     [(rule-type origin name clauses ...)
@@ -253,7 +253,7 @@
     #`[(translated-pattern ...)
        (rule-components->syntax '#,rule-name/false translated-action ...
                                 #:srcloc #,whole-rule-loc
-                                #:splice? #,(syntax-property rule-name/false 'hide))]))
+                                #:splice? #,(syntax-property rule-name/false 'splice))]))
 
 
 
diff --git a/brag/brag/rules/rule-structs.rkt b/brag/brag/rules/rule-structs.rkt
index b4d64af..33a2e8d 100755
--- a/brag/brag/rules/rule-structs.rkt
+++ b/brag/brag/rules/rule-structs.rkt
@@ -12,7 +12,7 @@
 (struct rule (start end lhs pattern)
         #:transparent)
 
-(struct lhs-id (start end val hide)
+(struct lhs-id (start end val splice)
         #:transparent)
 
 
diff --git a/brag/brag/rules/stx.rkt b/brag/brag/rules/stx.rkt
index 80197b5..a0f7b84 100755
--- a/brag/brag/rules/stx.rkt
+++ b/brag/brag/rules/stx.rkt
@@ -33,7 +33,7 @@
                               (- (pos-offset (lhs-id-end (rule-lhs a-rule)))
                                  (pos-offset (lhs-id-start (rule-lhs a-rule))))
                               #f)))
-     'hide (lhs-id-hide (rule-lhs a-rule))))
+     'splice (lhs-id-splice (rule-lhs a-rule))))
   (define pattern-stx (pattern->stx source (rule-pattern a-rule)))
   (define line (pos-line (rule-start a-rule)))
   (define column (pos-col (rule-start a-rule)))

From 07350988e7875f7cf5f8ddda40d5afef007e0929 Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Fri, 6 May 2016 13:32:36 -0700
Subject: [PATCH 07/13] make hider/splicer tests

---
 brag/brag/codegen/codegen.rkt                            | 3 ++-
 brag/brag/codegen/runtime.rkt                            | 6 +++---
 brag/brag/elider/json-elider-toy.rkt                     | 4 ----
 brag/brag/elider/test-json-elider-toy.rkt                | 9 ---------
 .../json-elider.rkt => examples/baby-json-hider.rkt}     | 5 ++---
 .../test-baby-json-hider.rkt}                            | 4 ++--
 6 files changed, 9 insertions(+), 22 deletions(-)
 delete mode 100644 brag/brag/elider/json-elider-toy.rkt
 delete mode 100644 brag/brag/elider/test-json-elider-toy.rkt
 rename brag/brag/{elider/json-elider.rkt => examples/baby-json-hider.rkt} (78%)
 rename brag/brag/{elider/test-json-elider.rkt => test/test-baby-json-hider.rkt} (90%)

diff --git a/brag/brag/codegen/codegen.rkt b/brag/brag/codegen/codegen.rkt
index b58f8df..75837c9 100755
--- a/brag/brag/codegen/codegen.rkt
+++ b/brag/brag/codegen/codegen.rkt
@@ -247,7 +247,8 @@
         (with-syntax ([$1-start-pos (datum->syntax (first translated-patterns) '$1-start-pos)]
                       [$n-end-pos (format-id (last translated-patterns) "$~a-end-pos" (length translated-patterns))])
           #`(positions->srcloc $1-start-pos $n-end-pos))))
-  
+
+  ;; move 'splice property into function because name is datum-ized
   (with-syntax ([(translated-pattern ...) translated-patterns]
                 [(translated-action ...) translated-actions])
     #`[(translated-pattern ...)
diff --git a/brag/brag/codegen/runtime.rkt b/brag/brag/codegen/runtime.rkt
index ebb8902..12212ca 100755
--- a/brag/brag/codegen/runtime.rkt
+++ b/brag/brag/codegen/runtime.rkt
@@ -163,15 +163,15 @@ This would be the place to check a syntax property for hiding.
 ;; Creates an stx out of the rule name and its components.
 ;; The location information of the rule spans that of its components.
 (define (rule-components->syntax rule-name/false #:srcloc [srcloc #f] #:splice? [splice #f] . componentss)
-  (let ([componentss (append-map (λ(cs)
+  (let ([spliced-componentss (append-map (λ(cs)
                                    (if (and (pair? cs) (syntax-property (car cs) 'splice))
-                                            (list (cdr (syntax->list (car cs))))
+                                            (list (cdr (syntax->list (car cs)))) ; pop off the rule name and splice its components into this rule
                                             (list cs))) componentss)])
     (syntax-property
      (datum->syntax #f 
                     (cons
                      (datum->syntax #f rule-name/false srcloc stx-with-original?-property)
-                     (apply append componentss))
+                     (apply append spliced-componentss))
                     srcloc
                     stx-with-original?-property)
      'splice splice)))
\ No newline at end of file
diff --git a/brag/brag/elider/json-elider-toy.rkt b/brag/brag/elider/json-elider-toy.rkt
deleted file mode 100644
index 8eed9e8..0000000
--- a/brag/brag/elider/json-elider-toy.rkt
+++ /dev/null
@@ -1,4 +0,0 @@
-#lang brag
-
-thing : foo
-foo : <"bar">
diff --git a/brag/brag/elider/test-json-elider-toy.rkt b/brag/brag/elider/test-json-elider-toy.rkt
deleted file mode 100644
index c3072c3..0000000
--- a/brag/brag/elider/test-json-elider-toy.rkt
+++ /dev/null
@@ -1,9 +0,0 @@
-#lang br
-(require "json-elider-toy.rkt"
-         brag/support
-         rackunit)
-
-(check-equal?
- (syntax->datum
-  (parse (list "bar")))
- '(thing))
diff --git a/brag/brag/elider/json-elider.rkt b/brag/brag/examples/baby-json-hider.rkt
similarity index 78%
rename from brag/brag/elider/json-elider.rkt
rename to brag/brag/examples/baby-json-hider.rkt
index 677a02d..eb2097f 100755
--- a/brag/brag/elider/json-elider.rkt
+++ b/brag/brag/examples/baby-json-hider.rkt
@@ -1,8 +1,7 @@
 #lang brag
 
 ;; Simple baby example of JSON structure
-json: number
-    | string
+json: number | string
     | array
     | object
 
@@ -14,4 +13,4 @@ array: "[" [json ("," json)*] "]"
 
 object: <"{"> [kvpair ("," kvpair)*] <"}">
 
-<kvpair> : <ID> ":" <json>
+<kvpair>: <ID> ":" <json>
diff --git a/brag/brag/elider/test-json-elider.rkt b/brag/brag/test/test-baby-json-hider.rkt
similarity index 90%
rename from brag/brag/elider/test-json-elider.rkt
rename to brag/brag/test/test-baby-json-hider.rkt
index c7e48d0..81af1a1 100755
--- a/brag/brag/elider/test-json-elider.rkt
+++ b/brag/brag/test/test-baby-json-hider.rkt
@@ -1,5 +1,5 @@
-#lang br
-(require "json-elider.rkt"
+#lang racket/base
+(require brag/examples/baby-json-hider
          brag/support
          rackunit)
 

From 7a4999ee36cf2e5e9d1951085a9d8a5ad3f1fa3c Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Fri, 6 May 2016 13:34:43 -0700
Subject: [PATCH 08/13] cleanup

---
 brag/brag/codegen/codegen.rkt | 18 ------------------
 1 file changed, 18 deletions(-)

diff --git a/brag/brag/codegen/codegen.rkt b/brag/brag/codegen/codegen.rkt
index 75837c9..2ef8499 100755
--- a/brag/brag/codegen/codegen.rkt
+++ b/brag/brag/codegen/codegen.rkt
@@ -38,26 +38,10 @@
        
        ;; We flatten the rules so we can use the yacc-style ruleset that parser-tools
        ;; supports.
-       
-       #|
-       MB: `rules` still carries 'hide syntax property
-       |#
-       #;(report rules)
-       
-       
-       #|
-       MB: `flattened-rules` still carries 'hide syntax property
-       |#
        (define flattened-rules (flatten-rules rules))
-       #;(report flattened-rules)
        
        (define generated-rule-codes (map flat-rule->yacc-rule flattened-rules))
        
-       #|
-       MB: `generated-rule-codes` loses the 'hide syntax property (but lhs-ids carry 'splice)
-       |#
-       #;(report generated-rule-codes)
-       
        ;; The first rule, by default, is the start rule.
        (define rule-ids (for/list ([a-rule (in-list rules)])
                                   (rule-id a-rule)))
@@ -179,8 +163,6 @@
 ;;     stx :== (name (U tokens rule-stx) ...)
 ;;
 (define (flat-rule->yacc-rule a-flat-rule)
-  ;; lhs-ids still carry 'splice property on #'name field
-  #;(report a-flat-rule)
   (syntax-case a-flat-rule ()
     [(rule-type origin name clauses ...)
      (begin

From 87f5b186a2ba09f78ef0345a9ecef05e3e224546 Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Fri, 6 May 2016 13:43:02 -0700
Subject: [PATCH 09/13] more cleanup

---
 brag/brag/codegen/codegen.rkt  | 2 +-
 brag/brag/codegen/flatten.rkt  | 2 +-
 brag/brag/codegen/runtime.rkt  | 2 +-
 brag/brag/rules/parser.rkt     | 4 ++--
 brag/brag/rules/stx.rkt        | 2 +-
 brag/brag/test/test-all.rkt    | 2 +-
 brag/brag/test/test-parser.rkt | 2 +-
 brag/info.rkt                  | 2 +-
 8 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/brag/brag/codegen/codegen.rkt b/brag/brag/codegen/codegen.rkt
index 2ef8499..544c5a0 100755
--- a/brag/brag/codegen/codegen.rkt
+++ b/brag/brag/codegen/codegen.rkt
@@ -1,4 +1,4 @@
-#lang br
+#lang racket/base
 
 (require (for-template racket/base)
          racket/list
diff --git a/brag/brag/codegen/flatten.rkt b/brag/brag/codegen/flatten.rkt
index a6a9fb6..e1d9baf 100755
--- a/brag/brag/codegen/flatten.rkt
+++ b/brag/brag/codegen/flatten.rkt
@@ -1,4 +1,4 @@
-#lang br
+#lang racket/base
 (require brag/rules/stx-types
          (for-syntax racket/base))
 
diff --git a/brag/brag/codegen/runtime.rkt b/brag/brag/codegen/runtime.rkt
index 12212ca..03235da 100755
--- a/brag/brag/codegen/runtime.rkt
+++ b/brag/brag/codegen/runtime.rkt
@@ -1,4 +1,4 @@
-#lang br
+#lang racket/base
 
 (require racket/match 
          racket/list
diff --git a/brag/brag/rules/parser.rkt b/brag/brag/rules/parser.rkt
index 5a318dc..1c74802 100755
--- a/brag/brag/rules/parser.rkt
+++ b/brag/brag/rules/parser.rkt
@@ -1,4 +1,4 @@
-#lang br
+#lang racket/base
 (require parser-tools/yacc
          parser-tools/lex
          racket/list
@@ -88,7 +88,7 @@
                       #f)
               $2))]
      
-     ;; angles indicate hiding. set hide value to #t
+     ;; angles indicate splicing. set splice value to #t
      [(RULE_HEAD_HIDDEN pattern)
       (begin
         (begin 
diff --git a/brag/brag/rules/stx.rkt b/brag/brag/rules/stx.rkt
index a0f7b84..c481911 100755
--- a/brag/brag/rules/stx.rkt
+++ b/brag/brag/rules/stx.rkt
@@ -1,4 +1,4 @@
-#lang br
+#lang racket/base
 
 (require "rule-structs.rkt"
          parser-tools/lex
diff --git a/brag/brag/test/test-all.rkt b/brag/brag/test/test-all.rkt
index 8917aec..f23fabe 100755
--- a/brag/brag/test/test-all.rkt
+++ b/brag/brag/test/test-all.rkt
@@ -1,4 +1,4 @@
-#lang br
+#lang racket/base
 
 
 (require "test-0n1.rkt"
diff --git a/brag/brag/test/test-parser.rkt b/brag/brag/test/test-parser.rkt
index 94adba1..22fcd98 100755
--- a/brag/brag/test/test-parser.rkt
+++ b/brag/brag/test/test-parser.rkt
@@ -1,4 +1,4 @@
-#lang br
+#lang racket/base
 
 
 (require rackunit
diff --git a/brag/info.rkt b/brag/info.rkt
index 810a1d4..45a38e2 100755
--- a/brag/info.rkt
+++ b/brag/info.rkt
@@ -1,6 +1,6 @@
 #lang setup/infotab
 
-(define deps '("base" "beautiful-racket-lib" "parser-tools-lib" "rackunit-lib" "python-tokenizer"))
+(define deps '("base" "parser-tools-lib" "rackunit-lib" "python-tokenizer"))
 (define build-deps '("at-exp-lib" "parser-tools-doc" "racket-doc"
                      "scribble-lib"))
 (define collection 'multi)

From feec0f85d5da14a3a9ec5fa2d974d3ed0c4f455f Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Fri, 6 May 2016 13:48:55 -0700
Subject: [PATCH 10/13] better regexp

---
 brag/brag/rules/parser.rkt | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/brag/brag/rules/parser.rkt b/brag/brag/rules/parser.rkt
index 1c74802..a00f44f 100755
--- a/brag/brag/rules/parser.rkt
+++ b/brag/brag/rules/parser.rkt
@@ -91,8 +91,7 @@
      ;; angles indicate splicing. set splice value to #t
      [(RULE_HEAD_HIDDEN pattern)
       (begin
-        (begin 
-        (define trimmed (cadr (regexp-match #px"<(\\w+)>\\s*:$" $1)))
+        (define trimmed (regexp-match #px"<(.+)>\\s*:$" $1))
         (rule (position->pos $1-start-pos)
               (position->pos $2-end-pos)
               (lhs-id (position->pos $1-start-pos)
@@ -102,7 +101,7 @@
                            (position-col $1-start-pos))
                       trimmed
                       #t)
-              $2)))]]
+              $2))]]
     
     [pattern
      [(implicit-pattern-sequence PIPE pattern)

From 0f9e8018ead7f9e180210d04cf208ad5e9c485d2 Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Fri, 6 May 2016 13:50:01 -0700
Subject: [PATCH 11/13] whoops

---
 brag/brag/rules/parser.rkt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/brag/brag/rules/parser.rkt b/brag/brag/rules/parser.rkt
index a00f44f..d348980 100755
--- a/brag/brag/rules/parser.rkt
+++ b/brag/brag/rules/parser.rkt
@@ -91,7 +91,7 @@
      ;; angles indicate splicing. set splice value to #t
      [(RULE_HEAD_HIDDEN pattern)
       (begin
-        (define trimmed (regexp-match #px"<(.+)>\\s*:$" $1))
+        (define trimmed (cadr (regexp-match #px"<(.+)>\\s*:$" $1)))
         (rule (position->pos $1-start-pos)
               (position->pos $2-end-pos)
               (lhs-id (position->pos $1-start-pos)

From fd5c53f019c3dc48e3d8294631ca9ba80d26591a Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Fri, 6 May 2016 14:46:04 -0700
Subject: [PATCH 12/13] victory

---
 beautiful-racket/br/demo/txtadv/expander.rkt | 55 +++++---------------
 beautiful-racket/br/demo/txtadv/parser.rkt   | 18 +++----
 brag/brag/codegen/runtime.rkt                |  4 +-
 brag/brag/test/test-baby-json-hider.rkt      |  2 +-
 4 files changed, 23 insertions(+), 56 deletions(-)

diff --git a/beautiful-racket/br/demo/txtadv/expander.rkt b/beautiful-racket/br/demo/txtadv/expander.rkt
index 2c64400..b07c10f 100644
--- a/beautiful-racket/br/demo/txtadv/expander.rkt
+++ b/beautiful-racket/br/demo/txtadv/expander.rkt
@@ -30,61 +30,30 @@
        (parameterize ([cmd-line-mode? #t])
          (do-place)))))
 
+
 (provide txtadv-program)
-(define #'(txtadv-program _section ...)
-  #'(module-begin _section ...))
+(define #'txtadv-program #'module-begin)
 
 (provide verb-section)
-(define-inverting #'(verb-section _verb-item ...)
+(define #'(verb-section
+           ((_name0 . _transitive0?)
+            (_name . _transitive?) ... _desc) ...)
   (inject-syntax ([#'in-verbs (shared-syntax 'in-verbs)])
                  #'(define-verbs in-verbs
-                     _verb-item ...)))
-
-
-(provide verb-item)
-(define-inverting #'(verb-item (_name0 _transitive0?) (_name _transitive?) ... _desc)
-  #`[_name0 #,@(if (syntax->datum #'_transitive0?) #'(_) #'()) (= _name ...) _desc])
-
-(provide verb-name)
-(define-cases #'verb-name
-  [#'(_ _id) #'(_id #f)]
-  [#'(_ _id _underscore) #'(_id #t)])
+                     [_name0 #,@(if (syntax->datum #'_transitive0?) #'(_) #'()) (= _name ...) _desc] ...)))
 
 (provide everywhere-section)
-(define-inverting #'(everywhere-section [_name _desc] ...)
+(define #'(everywhere-section [_id _desc] ...)
   #'(define-everywhere everywhere-actions
-      ([_name _desc] ...)))
-
-(provide id-desc)
-(define-inverting #'(id-desc _id _desc)
-  #'(_id _desc))
+      ([_id _desc] ...)))
 
 (provide things-section)
-(define-inverting #'(things-section _thing ...)
-  #'(begin _thing ...))
-
-(provide thing-item)
-(define-inverting #'(thing-item _thingname (_actionname _actiondesc) ...)
-  #'(define-thing _thingname [_actionname _actiondesc] ...))
+(define #'(things-section (_thingname (_actionname _actiondesc) ...) ...)
+  #'(begin (define-thing _thingname [_actionname _actiondesc] ...) ...))
 
 (provide places-section)
-(define-inverting #'(places-section _placeitem ...)
-  #'(begin _placeitem ...))
-
-(provide place-item)
-(define-inverting #'(place-item _place-id _place-desc [_place-item ...] [_actionname _actiondesc] ...)
-  #'(define-place _place-id _place-desc [_place-item ...] ([_actionname _actiondesc] ...)))
-
-(provide place-descrip)
-(define #'(place-descrip _desc) #'_desc)
-
-(provide place-items)
-(define-inverting #'(place-items _id ...) #'(_id ...))
-
-(provide place-name)
-(define-cases #'place-name
-  [#'(_ _id) #'_id])
-
+(define #'(places-section (_place-id _place-desc [_place-item ...] [_actionname _actiondesc] ...) ...)
+  #'(begin (define-place _place-id _place-desc [_place-item ...] ([_actionname _actiondesc] ...)) ...))
 
 (provide s-exp)
 (define-cases-inverting #'s-exp
diff --git a/beautiful-racket/br/demo/txtadv/parser.rkt b/beautiful-racket/br/demo/txtadv/parser.rkt
index 9a0798c..91c08f1 100644
--- a/beautiful-racket/br/demo/txtadv/parser.rkt
+++ b/beautiful-racket/br/demo/txtadv/parser.rkt
@@ -4,28 +4,24 @@ txtadv-program : verb-section everywhere-section things-section places-section s
 
 verb-section : <"===VERBS==="> verb-item+
 
-verb-item : verb-name+ s-exp
+<verb-item> : verb-name+ s-exp
 
-verb-name : [<",">] ID ["_"]
+<verb-name> : [<",">] ID ["_"]
 
 everywhere-section : <"===EVERYWHERE==="> id-desc+
 
 things-section : <"===THINGS==="> thing-item+
 
-thing-item : DASHED-NAME id-desc+
+<thing-item> : DASHED-NAME id-desc+
 
 places-section : <"===PLACES==="> place-item+
 
-place-item : DASHED-NAME place-descrip place-items id-desc+
+<place-item> : DASHED-NAME STRING place-items id-desc+
 
-place-descrip : STRING ; `place-desc` is already used in expander
+<place-items> : <"["> ([<",">] ID)* <"]">
 
-place-items : <"["> place-name* <"]"> ; `place-things` is already used
+start-section : <"===START==="> ID
 
-place-name : [<",">] ID
-
-start-section : <"===START==="> place-name
-
-id-desc : ID s-exp
+<id-desc> : ID s-exp
 
 s-exp : ID | STRING | <"("> s-exp* <")">
\ No newline at end of file
diff --git a/brag/brag/codegen/runtime.rkt b/brag/brag/codegen/runtime.rkt
index 03235da..bfa28da 100755
--- a/brag/brag/codegen/runtime.rkt
+++ b/brag/brag/codegen/runtime.rkt
@@ -165,7 +165,9 @@ This would be the place to check a syntax property for hiding.
 (define (rule-components->syntax rule-name/false #:srcloc [srcloc #f] #:splice? [splice #f] . componentss)
   (let ([spliced-componentss (append-map (λ(cs)
                                    (if (and (pair? cs) (syntax-property (car cs) 'splice))
-                                            (list (cdr (syntax->list (car cs)))) ; pop off the rule name and splice its components into this rule
+                                            (list (list (syntax-case (car cs) ()
+                                                    [(rule-name c ...)
+                                                     #'(c ...)])))
                                             (list cs))) componentss)])
     (syntax-property
      (datum->syntax #f 
diff --git a/brag/brag/test/test-baby-json-hider.rkt b/brag/brag/test/test-baby-json-hider.rkt
index 81af1a1..fb64dd6 100755
--- a/brag/brag/test/test-baby-json-hider.rkt
+++ b/brag/brag/test/test-baby-json-hider.rkt
@@ -10,7 +10,7 @@
                ":"
                (token 'STRING "'hello world'")
                "}")))
- '(json (object ":")))
+ '(json (object (":"))))
 
 
 (check-equal? 

From 245a488ac0322691e46f52ebeb83c7fae10c66e0 Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Fri, 6 May 2016 14:50:11 -0700
Subject: [PATCH 13/13] note

---
 beautiful-racket/br/demo/txtadv/expander.rkt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/beautiful-racket/br/demo/txtadv/expander.rkt b/beautiful-racket/br/demo/txtadv/expander.rkt
index b07c10f..6c714ab 100644
--- a/beautiful-racket/br/demo/txtadv/expander.rkt
+++ b/beautiful-racket/br/demo/txtadv/expander.rkt
@@ -31,6 +31,9 @@
          (do-place)))))
 
 
+;; ==============================================================
+;; Process parse trees from the reader:
+
 (provide txtadv-program)
 (define #'txtadv-program #'module-begin)