From 99f97b399c520a91dfa71fe1f49ac54720f99a8a Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Sun, 10 Jun 2018 20:34:22 -0700
Subject: [PATCH] forward

---
 brag/codegen/flatten.rkt | 30 +++++++++++++++++++++---------
 brag/rules/lexer.rkt     |  6 ++----
 brag/rules/parser.rkt    | 15 ++++++++++-----
 3 files changed, 33 insertions(+), 18 deletions(-)

diff --git a/brag/codegen/flatten.rkt b/brag/codegen/flatten.rkt
index ad3ecfc..aeb1902 100755
--- a/brag/codegen/flatten.rkt
+++ b/brag/codegen/flatten.rkt
@@ -1,7 +1,8 @@
 #lang racket/base
 (require brag/rules/stx-types
+         racket/list
          (for-syntax racket/base))
-
+(require (except-in sugar/debug repeat))
 (provide flatten-rule
          flatten-rules
          prim-rule)
@@ -102,21 +103,32 @@
             (begin
               (define-values (inferred-rules new-sub-pats)
                 (lift-nonprimitive-pattern #'sub-pat))
-              (with-syntax ([(sub-pat ...) new-sub-pats])
+              (report/file (syntax-e #'min))
+              (with-syntax ([(sub-pat ...) new-sub-pats]
+                            [MIN-REPEAT-SUB-PATS (apply append (make-list (syntax-e #'min) new-sub-pats))])
                 (cons (cond [(= (syntax-e #'min) 0)
-                             #`(head origin name
-                                     [(inferred-id name repeat) sub-pat ...]
-                                     [])]
-                            [(= (syntax-e #'min) 1)
-                             #`(head origin name
-                                     [(inferred-id name repeat) sub-pat ...]
-                                     [sub-pat ...])])
+                               #`(head origin name
+                                       [(inferred-id name repeat) sub-pat ...]
+                                       [])]
+                              [(= (syntax-e #'min) 1)
+                               #`(head origin name
+                                       [(inferred-id name repeat) sub-pat ...]
+                                       [sub-pat ...])]
+                              [(= (syntax-e #'min) 2)
+                               #`(head origin name
+                                       [(inferred-id name repeat) sub-pat ...]
+                                       [sub-pat ... sub-pat ...])])
+                        inferred-rules)
+                #;(cons (report/file #`(head origin name
+                              [(inferred-id name repeat) sub-pat ...]
+                              MIN-REPEAT-SUB-PATS))
                       inferred-rules)))]
 
            [(maybe sub-pat)
             (begin
               (define-values (inferred-rules new-sub-pats)
                 (lift-nonprimitive-pattern #'sub-pat))
+              (report*/file #'pat #'sub-pat)
               (with-syntax ([(sub-pat ...) new-sub-pats])
                 (cons #'(head origin name
                               [sub-pat ...]
diff --git a/brag/rules/lexer.rkt b/brag/rules/lexer.rkt
index b5a485e..44e8d13 100755
--- a/brag/rules/lexer.rkt
+++ b/brag/rules/lexer.rkt
@@ -65,10 +65,8 @@
    ["|"
     (token-PIPE lexeme)]
    [(:or "+" "*"
-         ;; todo: consolidate next two patterns?
-         (:: "{" (:* digit) "}")
-         (:: "{" (:* digit) "," (:* digit) "}"))
-    (token-REPEAT (let () (println lexeme) lexeme))]
+         (:: "{" (:* digit) (:? (:: "," (:* digit))) "}"))
+    (token-REPEAT lexeme)]
    [whitespace
     ;; Skip whitespace
     (return-without-pos (lex/1 input-port))]
diff --git a/brag/rules/parser.rkt b/brag/rules/parser.rkt
index 05cfa9a..93c794e 100755
--- a/brag/rules/parser.rkt
+++ b/brag/rules/parser.rkt
@@ -4,6 +4,7 @@
          racket/list
          racket/match
          "rule-structs.rkt")
+(require sugar/debug)
 
 ;; A parser for grammars.
 
@@ -162,12 +163,16 @@
              (pattern-repeat (position->pos $1-start-pos)
                              (position->pos $2-end-pos)
                              1 $1)]
-            [(regexp-match #px"^\\{(\\d+)?,?(\\d+)?\\}$" $2)
+            [(regexp-match #px"^\\{(\\d+)?,?(\\d+)?\\}$" $2) ; "{min,max}" with both min & max optional
              => (λ (m)
-                  (define pr (match m
-                      [(list _ min max) (cons (and min (string->number min))
-                                                (and max (string->number max)))]))
-                  (error (format "~a" pr)))]
+                  (match-define (cons min-repeat max-repeat)
+                    (match m
+                      [(list _ min max) (cons (if min (string->number min) 0)
+                                              (and max (string->number max)))]))
+                  (report/file min-repeat)
+                  (pattern-repeat (position->pos $1-start-pos)
+                                  (position->pos $2-end-pos)
+                                  min-repeat $1))]
             [else
              (error 'grammar-parse "unknown repetition operator ~e" $2)])]
      [(atomic-pattern)