From 2a1002fa94cefb4416f9a3c29f5af1f2fd239d36 Mon Sep 17 00:00:00 2001
From: Rodrigo Ribeiro <rodrigogribeiro@gmail.com>
Date: Mon, 11 Apr 2022 19:59:34 -0300
Subject: [PATCH] More PEG operators

---
 examples/test13.rkt |  4 ++++
 grammar.rkt         | 13 +++++++++++--
 lexer.rkt           | 23 ++++++++++++++++++++++-
 3 files changed, 37 insertions(+), 3 deletions(-)
 create mode 100644 examples/test13.rkt

diff --git a/examples/test13.rkt b/examples/test13.rkt
new file mode 100644
index 0000000..7973bcf
--- /dev/null
+++ b/examples/test13.rkt
@@ -0,0 +1,4 @@
+#lang typed-peg/debug/parse-only
+
+start: & "a" / "bb" +
+
diff --git a/grammar.rkt b/grammar.rkt
index 4da223e..e6e1195 100644
--- a/grammar.rkt
+++ b/grammar.rkt
@@ -10,6 +10,7 @@
 (define (string->tree s)
   (match s
     ['() (peps)]
+    [(cons c '()) (pchr c)]
     [(cons c s1) (pcat (pchr c)
                        (string->tree s1))]))
 
@@ -32,13 +33,21 @@
           [(cat) $1])
     (cat [(cat term) (pcat $1 $2)]
          [(term) $1])
-    (term [(NOT term) (pneg $2)]
+    (term [(prefixop term) ($1 $2)]
           [(factor)   $1])
-    (factor [(factor STAR) (pstar $1)]
+    (prefixop [(NOT) (lambda (e) (pneg e))]
+              [(AND) (lambda (e) (pneg (pneg e)))])
+    (factor [(factor postfix) ($2 $1)]
             [(atom) $1])
+    (postfix [(STAR) (lambda (e) (pstar e))]
+             [(PLUS) (lambda (e) (pcat e (pstar e)))]
+             [(OPTION) (lambda (e) (pchoice e peps))])
+    (char-list [(CHAR) (pchr (car (string->list $1)))]
+               [(CHAR COMMA char-list) (pchoice $1 $3)])
     (atom [(EPSILON) (peps)]
           [(CHAR)    (pchr (car (string->list $1)))]
           [(STRING)  (string->tree (string->list $1))]
+          [(LBRACK char-list RBRACK) $2]
           [(ANY)     (pany)]
           [(VAR)     (pvar $1)]
           [(LPAREN expr RPAREN) $2])
diff --git a/lexer.rkt b/lexer.rkt
index 2539019..e61b71e 100644
--- a/lexer.rkt
+++ b/lexer.rkt
@@ -7,15 +7,36 @@
   (CHAR VAR STRING))
 
 (define-empty-tokens op-tokens
-  (EOF OR LPAREN RPAREN STAR NOT SEMI EPSILON ARROW START ANY))
+  (EOF OR
+       LPAREN
+       RPAREN
+       STAR
+       NOT
+       SEMI
+       EPSILON
+       ARROW
+       START
+       ANY
+       PLUS
+       OPTION
+       AND
+       LBRACK
+       RBRACK
+       COMMA))
 
 (define next-token
   (lexer-src-pos
    [(eof) (token-EOF)]
    [(:+ whitespace #\newline) (return-without-pos (next-token input-port))]
    ["." (token-ANY)]
+   ["," (token-COMMA)]
+   ["[" (token-LBRACK)]
+   ["]" (token-RBRACK)]
    ["/" (token-OR)]
+   ["+" (token-PLUS)]
+   ["?" (token-OPTION)]
    ["*" (token-STAR)]
+   ["&" (token-AND)]
    ["<--" (token-ARROW)]
    ["!" (token-NOT)]
    [";" (token-SEMI)]