From 5426d9e2a6b820e34809d639838b26643df9ab17 Mon Sep 17 00:00:00 2001
From: JSDurand <mmemmew@gmail.com>
Date: Tue, 8 Feb 2022 00:29:10 +0800
Subject: fix errors

There are multiple subtle errors in the previous version, both in the
codes and in the description of the BNF format.  This version should
fix some problems now.

This version can successfully parse the grammar of its own grammar
format, which is quite nice.  See test/check_reader.c for parsing this
format.
---
 src/bnf.bnf | 81 +++++++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 55 insertions(+), 26 deletions(-)

(limited to 'src/bnf.bnf')

diff --git a/src/bnf.bnf b/src/bnf.bnf
index df8ef3c..0a339fc 100644
--- a/src/bnf.bnf
+++ b/src/bnf.bnf
@@ -1,27 +1,41 @@
 # A grammar file for reading BNF notation
+# FIXME: Too many errors!
 
-[id]: a-zA-Z-_+*@
+[space]: %x20\t
 
-[notbracket]: ^[]
+[id]: a-zA-Z\-_+*@
+
+[rule_name_char]: ^[]:%x20\n
 
 [notnewline]: ^\n\r
 
+[class_range_char]: ^\n\r\^\\
+
+[class_single_char]: ^\n\r\^\\\-
+
+[any]:
+
+[double_string_char]: ^"\n
+
+[single_string_char]: ^'\n
+
 --
 
-BNF: predicate_section "--\n" rules_section
+BNF: "#" notnewlines empty BNF
+BNF: predicate_section "--\n" empty rules_section
 BNF: rules_section
 BNF:
 
-spaces: space spaces
-spaces: space
+spaces: [space] spaces
+spaces: [space]
 
-space: " "
-space: "\t"
+optional_spaces: [space] optional_spaces
+optional_spaces:
 
-empty: spaces empty
-empty: "\n" empty "\n"
-empty: "\r" empty "\n"
-empty: "#" notnewlines "\n"
+empty: [space] empty
+empty: "\n" empty
+empty: "\r" empty
+empty: "\n#" notnewlines
 empty:
 
 notnewlines: [notnewline] notnewlines
@@ -30,13 +44,13 @@ notnewlines:
 predicate_section: predicate empty "\n" predicate_section
 predicate_section:
 
-predicate: "[" ids "]:" spaces class
+predicate: "[" ids "]:" optional_spaces class
 
 ids: [id] ids
-ids:
+ids: [id]
 
 # Yes, a class specification can be empty, in which case the predicate
-# is equivalent with the default "any" predicate.
+# matches everything.
 
 class: positive_class
 class: "^" positive_class
@@ -44,23 +58,38 @@ class: "^" positive_class
 positive_class: positive_specification positive_class
 positive_class:
 
-positive_specification: enotnewline
-positive_specification: enotnewline "-" enotnewline
+positive_specification: class_single_chars
+positive_specification: class_range_chars "-" class_range_chars
+
+class_single_chars: [class_single_char]
+class_single_chars: "\\" [any]
 
-# Extended not-newline, or escaped not-newline
-enotnewline: [notnewline]
-enotnewline: "\\" [any]
+class_range_chars: [class_range_char]
+class_range_chars: "\\" [any]
 
 rules_section: rule empty "\n" rules_section
+rules_section:
 
-rule: rule_name ":" spaces rule_rhs
-rule: rule_name ":" rule_rhs
+rule: rule_name optional_spaces ":" optional_spaces rule_rhs
 
-rule_name: [notbracket] rule_name
+rule_name: [rule_name_char] rule_name
 rule_name:
 
-spaces-or-escaped-newline: spaces
-spaces-or-escaped-newline: "\\\n"
+spaces_or_escaped_newline: optional_spaces
+spaces_or_escaped_newline: "\\\n"
+
+rule_rhs: ids spaces_or_escaped_newline rule_rhs
+rule_rhs: '[' ids ']' spaces_or_escaped_newline rule_rhs
+rule_rhs: '"' double_string_chars '"' spaces_or_escaped_newline rule_rhs
+rule_rhs: "'" single_string_chars "'" spaces_or_escaped_newline rule_rhs
+rule_rhs: 
+
+double_string_chars: [double_string_char]
+double_string_chars: "\\" [any]
+double_string_chars: [double_string_char] double_string_char
+double_string_chars: "\\" [any] double_string_chars
 
-rule_rhs: ids spaces-or-escaped-newline rule_rhs
-rule_rhs:
+single_string_chars: [single_string_char]
+single_string_chars: "\\" [any]
+single_string_chars: [single_string_char] single_string_char
+single_string_chars: "\\" [any] single_string_chars
-- 
cgit v1.2.3-18-g5258