1 files changed, 8 insertions, 0 deletions
diff --git a/src/js/extract_lsp.js b/src/js/extract_lsp.js
index 6f53ebc..358d404 100644
--- a/src/js/extract_lsp.js
+++ b/src/js/extract_lsp.js
@@ -3,6 +3,14 @@
 // the vm needs the layout, because the server's map is not the compiler's.
 const fs = require('fs');
 const path = require('path');
+if (process.argv.length > 2) {
+    if (process.argv.length === 3 && ['--help', '-h'].includes(process.argv[2])) {
+        console.log('usage: node src/js/extract_lsp.js [--help|-h]\nconverts build/lsp/genome.h and its memory map into src/js/lsp.json; build the lsp first.');
+        process.exit(0);
+    }
+    console.error('extract_lsp: unexpected arguments; use --help for usage');
+    process.exit(2);
+}
 
 const root = path.join(__dirname, '..', '..');
 const genome = fs.readFileSync(path.join(root, 'build', 'lsp', 'genome.h'), 'utf8');