From 907101b42159c3d2a8ee74540fb8e9259b36db7e Mon Sep 17 00:00:00 2001
From: Bruce Hill <bruce@bruce-hill.com>
Date: Mon, 28 Sep 2020 16:35:22 -0700
Subject: Fixes for captures and backrefs, and added block comments

---
 compiler.c             |  2 +-
 grammars/bpeg.bpeg     |  7 ++++---
 grammars/builtins.bpeg |  2 +-
 utils.c                | 16 +++++++++++++++-
 vm.c                   | 35 +++++++++++++----------------------
 5 files changed, 34 insertions(+), 28 deletions(-)

diff --git a/compiler.c b/compiler.c
index 49c4996..1f2d9ff 100644
--- a/compiler.c
+++ b/compiler.c
@@ -267,7 +267,7 @@ vm_op_t *bpeg_simplepattern(file_t *f, const char *str)
         case '@': {
             op->op = VM_CAPTURE;
             const char *a = *str == '!' ? &str[1] : after_name(str);
-            if (a > str && *after_spaces(a) == '=') {
+            if (a > str && a[0] == '=' && a[1] != '>') {
                 op->args.capture.name = strndup(str, (size_t)(a-str));
                 str = a + 1;
             }
diff --git a/grammars/bpeg.bpeg b/grammars/bpeg.bpeg
index 380bf9c..88dc6b1 100644
--- a/grammars/bpeg.bpeg
+++ b/grammars/bpeg.bpeg
@@ -49,7 +49,7 @@ Repeat: (
 Optional: `[ __ extended-pat (__`] / @!={=> "Expected closing square bracket here"})
 After: `< _ pat
 Before: `> _ pat
-Capture: `@ [_ `[ @capture-name=(...>(`]/$$)) (`] / @!={=>"Expected closing bracket here"})] _ @capture=pat
+Capture: `@ [_ @capture-name=(id/`!) !"=>" `=] _ (@capture=pat / @!={=> "Expected pattern to capture"})
 Replace: `{ __ (
       [@replace-pat=extended-pat __] "=>" [__ @replacement=String]
     ) __ (`} / @!={=> "Expected closing brace here"})
@@ -71,7 +71,8 @@ $:  !.
 
 id: "^^" / "^" / "__" / "_" / "$$" / "$" / (`a-z/`A-Z) 0+(`a-z/`A-Z/`0-9/`-)
 
-hash-comment: `# .. $
+line-comment: `# .. $
+block-comment: "#(" 0+(block-comment / !")#" .) ")#"
 
 # Note: comments are undefined by default in regular BPEG
-comment: hash-comment
+comment: block-comment / line-comment
diff --git a/grammars/builtins.bpeg b/grammars/builtins.bpeg
index 1633a30..c05b4c7 100644
--- a/grammars/builtins.bpeg
+++ b/grammars/builtins.bpeg
@@ -30,7 +30,7 @@ only-matches: (
     (include-binary-files / is-text-file)
     define-highlights
     add-filename
-    1+{...@hl-pattern=>'@1\n'}
+    1+{...@hl-pattern =>'@1\n'}
 )
 add-filename: [print-filenames (is-tty {=>"\033[33;1;4m@&:\033[0m\n"} / {=>"@&:\n"})]
 add-line-number: [print-line-numbers (is-tty {=>"\033[2m@#\033[5G|\033[0m "} / {=>"@#| "})]
diff --git a/utils.c b/utils.c
index 6b9af5c..012c1eb 100644
--- a/utils.c
+++ b/utils.c
@@ -9,6 +9,7 @@
  */
 const char *after_spaces(const char *str)
 {
+    int block_comment_depth = 0;
     // Skip whitespace and comments:
   skip_whitespace:
     switch (*str) {
@@ -17,7 +18,20 @@ const char *after_spaces(const char *str)
             goto skip_whitespace;
         }
         case '#': {
-            while (*str && *str != '\n') ++str;
+            if (str[1] == '(') {
+                ++block_comment_depth;
+                for (str += 2; *str && block_comment_depth > 0; ++str) {
+                    if (str[0] == '#' && str[1] == '(') {
+                        ++block_comment_depth;
+                        ++str;
+                    } else if (str[0] == ')' && str[1] == '#') {
+                        --block_comment_depth;
+                        ++str;
+                    }
+                }
+            } else {
+                while (*str && *str != '\n') ++str;
+            }
             goto skip_whitespace;
         }
     }
diff --git a/vm.c b/vm.c
index 5d749ec..1db4481 100644
--- a/vm.c
+++ b/vm.c
@@ -532,14 +532,14 @@ static match_t *get_cap(match_t *m, const char **r)
     if (isdigit(**r)) {
         int n = (int)strtol(*r, (char**)r, 10);
         return get_capture_n(m->child, &n);
-    } else if (**r == '[') {
-        char *closing = strchr(*r+1, ']');
-        if (!closing) return NULL;
-        ++(*r);
-        char *name = strndup(*r, (size_t)(closing-*r));
+    } else {
+        const char *end = after_name(*r);
+        if (end == *r) return NULL;
+        char *name = strndup(*r, (size_t)(end-*r));
         match_t *cap = get_capture_named(m, name);
         free(name);
-        *r = closing + 1;
+        *r = end;
+        if (*end == ';') ++(*r);
         return cap;
     }
     return NULL;
@@ -638,26 +638,17 @@ static match_t *match_backref(const char *str, vm_op_t *op, match_t *cap, unsign
                     cap = get_capture_n(cap->child, &n);
                     break;
                 }
-                case '[': {
-                    char *closing = strchr(r+1, ']');
-                    if (!closing) {
-                        if (*(str++) != '@') {
-                            destroy_match(&ret);
-                            return NULL;
-                        }
-                    }
-                    ++r;
-                    char *name = strndup(r, (size_t)(closing-r));
-                    cap = get_capture_named(cap, name);
-                    free(name);
-                    r = closing + 1;
-                    break;
-                }
                 default: {
-                    if (*(str++) != '@') {
+                    const char *end = after_name(r);
+                    if (end == r) {
                         destroy_match(&ret);
                         return NULL;
                     }
+                    char *name = strndup(r, (size_t)(end-r));
+                    cap = get_capture_named(cap, name);
+                    free(name);
+                    r = end;
+                    if (*r == ';') ++r;
                     break;
                 }
             }
-- 
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