From 544a88e9d4faa3f7e34316daaa01d2fa14d1d9f6 Mon Sep 17 00:00:00 2001
From: Bruce Hill <bruce@bruce-hill.com>
Date: Mon, 28 Sep 2020 17:42:38 -0700
Subject: Added +/*/? postfix operators

---
 README.md          |  6 ++++--
 bpeg.1             |  9 +++++++++
 compiler.c         | 28 ++++++++++++++++++++++++++--
 grammars/bpeg.bpeg | 18 +++++++++++-------
 4 files changed, 50 insertions(+), 11 deletions(-)

diff --git a/README.md b/README.md
index 66cbccf..b641de5 100644
--- a/README.md
+++ b/README.md
@@ -44,11 +44,13 @@ Pattern            | Meaning
 `\n`, `\033`, `\x0A`, etc. | An escape sequence character
 `\x00-xFF`         | An escape sequence range (byte `0x00` through `0xFF` here)
 `!pat`             | `pat` does not match at the current position
-`[pat]`            | Zero or one occurrences of `pat` (optional pattern)
+`[pat]` or `pat?`  | Zero or one occurrences of `pat` (optional pattern)
 `5 pat`            | Exactly 5 occurrences of `pat`
 `2-4 pat`          | Between 2 and 4 occurrences of `pat` (inclusive)
 `5+ pat`           | 5 or more occurrences of `pat`
-`0+ pat % sep`     | 0 or more occurrences of `pat`, separated by `sep` (e.g. `0+ int % ","` matches `1,2,3`)
+`5+ pat % sep`     | 5 or more occurrences of `pat`, separated by `sep` (e.g. `0+ int % ","` matches `1,2,3`)
+`pat*` `pat* % sep`| 0 or more occurrences of `pat` (optionally separated by `sep`)
+`pat+` `pat+ % sep`| 1 or more occurrences of `pat` (optionally separated by `sep`)
 `<pat`             | `pat` matches just before the current position (backref)
 `>pat`             | `pat` matches just in front of the current position (lookahead)
 `@pat`             | Capture `pat` (used for text replacement and backreferences)
diff --git a/bpeg.1 b/bpeg.1
index 3948b10..26b2a64 100644
--- a/bpeg.1
+++ b/bpeg.1
@@ -114,11 +114,20 @@ The \fBescape-sequence-range-\fI<esc1>\fB-to-\fI<esc2>\fR
 .B [\fI<pat>\fR]
 \fBMaybe-\fI<pat>\fR
 
+.B \fI<pat>\fR?
+\fI<pat>\fB-or-not\fR
+
 .B \fI<N> <pat>\fR
 .B \fI<MIN>\fB-\fI<MAX> <pat>\fR
 .B \fI<MIN>\fB+ \fI<pat>\fR
 \fI<MIN>\fB-to-\fI<MAX>\fB-\fI<pat>\fBs\fR (repetitions of a pattern)
 
+.B \fI<pat>\fR*
+\fI<pat>\fB-zero-or-more-times\fR
+
+.B \fI<pat>\fR+
+\fI<pat>\fB-one-or-more-times\fR
+
 .B \fI<repeating-pat>\fR \fB%\fI <sep>\fR
 \fI<repeating-pat>\fB-separated-by-\fI<sep>\fR (equivalent to \fI<pat>
 \fB0+(\fI<sep><pat>\fB)\fR)
diff --git a/compiler.c b/compiler.c
index ba53579..5faf0f2 100644
--- a/compiler.c
+++ b/compiler.c
@@ -24,6 +24,12 @@ static void set_range(vm_op_t *op, ssize_t min, ssize_t max, vm_op_t *pat, vm_op
     op->args.repetitions.max = max;
     op->args.repetitions.repeat_pat = pat;
     op->args.repetitions.sep = sep;
+    if (!op->start) op->start = pat->start;
+    if (!op->end) op->end = pat->end;
+    if (sep) {
+        if (sep->start < op->start) op->start = sep->start;
+        if (sep->end > op->end) op->end = sep->end;
+    }
 }
 
 /*
@@ -365,8 +371,26 @@ vm_op_t *bpeg_simplepattern(file_t *f, const char *str)
 
     // Postfix operators:
   postfix:
-    if (strncmp(after_spaces(str), "==", 2) == 0) {
-        str = after_spaces(str)+2;
+    if (f ? str >= f->end : !*str) return op;
+    str = after_spaces(str);
+    if (*str == '*' || *str == '+' || *str == '?') { // Repetitions: <pat>*, <pat>+, <pat>?
+        char operator = *str;
+        ++str;
+        vm_op_t *pat = op;
+        vm_op_t *sep = NULL;
+        if (operator != '?' && matchchar(&str, '%')) {
+            sep = bpeg_simplepattern(f, str);
+            check(sep, "Expected pattern for separator after '%%'");
+            str = sep->end;
+        }
+        op = calloc(sizeof(vm_op_t), 1);
+        set_range(op, operator == '+' ? 1 : 0, operator == '?' ? 1 : -1, pat, sep);
+        op->start = pat->start;
+        op->end = str;
+        op->len = -1;
+        goto postfix;
+    } else if (strncmp(str, "==", 2) == 0) { // Equality <pat1>==<pat2>
+        str = after_spaces(str+2);
         vm_op_t *first = op;
         vm_op_t *second = bpeg_simplepattern(f, str);
         check(second, "Expected pattern after '=='");
diff --git a/grammars/bpeg.bpeg b/grammars/bpeg.bpeg
index bf2386e..ce10bc1 100644
--- a/grammars/bpeg.bpeg
+++ b/grammars/bpeg.bpeg
@@ -9,17 +9,21 @@ Def: @name=id _ `: __ (
 # This is used for command line arguments:
 String-pattern: 0+(`\ (escape-sequence / pat [`;]) / .)
 
-pat: suffixed-pat / simple-pat
+pat: simple-pat !(__("=="/`*/`+/`?)) / suffixed-pat
 simple-pat: Upto-and / Dot / String / Char-range / Char / Escape-range / Escape / No
     / Nodent / Repeat / Optional / After / Before / Capture / Replace / Ref / parens
 
-suffixed-pat: Eq-pat / simple-pat [
-      @!={`* => "'*' is not a BPEG operator. Use 0+<pat> instead of <pat>*"}
-    / @!={`+ => "'+' is not a BPEG operator. Use 1+<pat> instead of <pat>+"}
-    / @!={`? => "'?' is not a BPEG operator. Use [<pat>] instead of <pat>?"}
-]
+suffixed-pat: (
+      Eq-pat
+    / Star-pat
+    / Plus-pat
+    / Question-pat
+)
 
-Eq-pat: @first=simple-pat "==" @second=pat
+Eq-pat: @first=pat__"=="__@second=pat
+Star-pat: pat __ `* @min={=>"0"} @max="" [__`%__@sep=pat]
+Plus-pat: pat __ `+ @min={=>"1"} @max="" [__`%__@sep=pat]
+Question-pat: pat __ `?
 
 Dot: `. !`.
 String: (
-- 
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