chore: Replace generate_grammar.py with generate-grammar.vsh (#204)

Co-authored-by: ge <gechandev@gmail.com>

.gitignore

@@ -4,9 +4,8 @@ vsql-server
 *.vsql
 .vscode
 .vlang_tmp_build/
-grammar.bnf
-vsql/grammar.v
 scripts/generate-v-client-library-docs
+scripts/generate-grammar
 y.output
 vsql/y.v
 vsql/y.y

Makefile

@@ -57,7 +57,7 @@ clean-docs:
 # Grammar
 
 vsql/y.y:
-	python3 scripts/generate_grammar.py
+	./scripts/generate-grammar.vsh
 
 vsql/y.v: vsql/y.y
 	v run scripts/vyacc.v -o vsql/y.v vsql/y.y

docs/faq.rst

@@ -44,15 +44,6 @@ available and these will be close enough to use as a reference:
 1. `SQL 2016 Foundation Grammar (BNF) <https://jakewheat.github.io/sql-overview/sql-2016-foundation-grammar.html>`_
 2. `SQL 1999 <https://crate.io/docs/sql-99/en/latest//>`_
 
-Wait! You said this is pure V but I see a Python file?
-------------------------------------------------------
-
-The python file ``generate-grammar.py`` is used to convert the BNF grammar into
-V code that makes up the parser. The result file ``grammar.v`` is committed so
-there is no need to use python to compile and otherwise work on vsql unless you
-need to change the grammar. However, if you would like to covert this script to
-V, I'd be happy to have your help!
-
 Why is there no `NOW()` function?
 ---------------------------------
 

scripts/generate-grammar.vsh

@@ -0,0 +1,40 @@
+#!/usr/bin/env -S v
+
+path := abs_path('vsql')
+output_filename := join_path_single(path, 'y.y')
+files := glob(join_path_single(path, '*.y')) or { [] }
+
+mut top := ''
+mut middle := ''
+mut bottom := ''
+
+for file_path in files {
+	if is_dir(file_path) {
+		continue
+	}
+	content := read_file(file_path) or {
+		eprintln('error: unable to open file ${file_path}: ${err}')
+		exit(1)
+	}
+	parts := content.split('%%')
+	if parts.len != 3 {
+		eprintln('${file_path}: wrong number of parts (${parts.len})')
+		exit(1)
+	}
+	top += parts[0]
+	middle += parts[1]
+	bottom += parts[2]
+}
+
+mut output := open_file(output_filename, 'w') or {
+	eprintln('error: unable to open file to write')
+	exit(1)
+}
+
+output.writeln(top.trim_space())!
+output.writeln('%%')!
+output.writeln(middle.trim_space())!
+output.writeln('%%')!
+output.write_string(bottom.trim_space())!
+output.flush()
+output.close()