go generate grammar sample in README.md

Author: marcelocantos

README.md

@@ -6,6 +6,7 @@
 
 ωBNF is self describing!
 
+<!-- INJECT: ```text\n${examples/wbnf.txt}\n``` -->
 ```text
 // Non-terminals
 grammar -> stmt+;
@@ -26,11 +27,11 @@ COMMENT -> /{ //.*$
             | (?s: /\* (?: [^*] | \*+[^*/] ) \*/ )
             };
 IDENT   -> /{@|[A-Za-z_\.]\w*};
+INT     -> /{\d+};
 STR     -> /{ " (?: \\. | [^\\"] )* "
             | ' (?: \\. | [^\\'] )* '
-            | ` (?: ``  | [^‵]   )* `
+            | ` (?: ``  | [^`]   )* `
             };
-INT     -> /{\d+};
 RE      -> /{
              /{
                ((?:
@@ -41,11 +42,12 @@ RE      -> /{
                )*)
              \}
            };
-REF     -> `\` IDENT;
+REF     -> "\\" IDENT;
 
 // Special
 .wrapRE -> /{\s*()\s*};
 ```
+<!-- /INJECT -->
 
 ## The basics
 

examples/wbnf.txt

@@ -13,12 +13,15 @@ quant   -> op=/{[?*+]}
 atom    -> IDENT | STR | RE | REF | "(" term ")" | "(" ")";
 
 // Terminals
+COMMENT -> /{ //.*$
+            | (?s: /\* (?: [^*] | \*+[^*/] ) \*/ )
+            };
 IDENT   -> /{@|[A-Za-z_\.]\w*};
+INT     -> /{\d+};
 STR     -> /{ " (?: \\. | [^\\"] )* "
             | ' (?: \\. | [^\\'] )* '
             | ` (?: ``  | [^`]   )* `
             };
-INT     -> /{\d+};
 RE      -> /{
              /{
                ((?:
@@ -29,10 +32,7 @@ RE      -> /{
                )*)
              \}
            };
-REF		-> "\\" IDENT;
-COMMENT -> /{ //.*$
-            | (?s: /\* (?: [^*] | \*+[^*/] ) \*/ )
-            };
+REF     -> "\\" IDENT;
 
 // Special
 .wrapRE -> /{\s*()\s*};

generate.go

@@ -0,0 +1,3 @@
+package main
+
+//go:generate scripts/inject.py -i README.md

wbnf/copygrammar.sh renamed to scripts/copygrammar.sh

@@ -1,7 +1,9 @@
-#!/bin/bash
+#!/bin/sh
 
 out=wbnfgrammar.go
+
 echo Generating $out
+
 cat > $out <<EOF
 package wbnf
 

scripts/inject.py

@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+
+import re
+import sys
+
+if sys.argv[1] == '-i':
+    sys.argv[1] =  sys.argv[2]
+
+with sys.stdin if sys.argv[1] == '-' else open(sys.argv[1]) as input:
+    result = re.sub(
+        r"(?s)(<!--\s*INJECT:\s*(.*?)\s*-->\n).*?(\n<!--\s*/INJECT\s*-->)",
+        lambda s:
+            s[1]
+            +
+            re.sub(
+                r"\$\{(.*?)}",
+                lambda f: open(f[1]).read().rstrip(),
+                s[2].replace(r"\n", "\n"),
+            )
+            +
+            s[3],
+        input.read(),
+    )
+
+with sys.stdout if sys.argv[2] == '-' else open(sys.argv[2], 'w') as output:
+    output.write(result)

wbnf/generate.go

@@ -1,3 +1,3 @@
 package wbnf
 
-//go:generate sh copygrammar.sh
+//go:generate ../scripts/copygrammar.sh

wbnf/wbnfgrammar.go

@@ -16,12 +16,15 @@ quant   -> op=/{[?*+]}
 atom    -> IDENT | STR | RE | REF | "(" term ")" | "(" ")";
 
 // Terminals
+COMMENT -> /{ //.*$
+            | (?s: /\* (?: [^*] | \*+[^*/] ) \*/ )
+            };
 IDENT   -> /{@|[A-Za-z_\.]\w*};
+INT     -> /{\d+};
 STR     -> /{ " (?: \\. | [^\\"] )* "
             | ' (?: \\. | [^\\'] )* '
             | ‵ (?: ‵‵  | [^‵]   )* ‵
             };
-INT     -> /{\d+};
 RE      -> /{
              /{
                ((?:
@@ -32,10 +35,7 @@ RE      -> /{
                )*)
              \}
            };
-REF		-> "\\" IDENT;
-COMMENT -> /{ //.*$
-            | (?s: /\* (?: [^*] | \*+[^*/] ) \*/ )
-            };
+REF     -> "\\" IDENT;
 
 // Special
 .wrapRE -> /{\s*()\s*};