add dump subcommand

Author: bobzhang

rescript

@@ -14,10 +14,15 @@ var fs = require("fs");
 var bsconfig = "bsconfig.json";
 
 /**
- * 
+ *
  * @type{string}
  */
-var bin_path = path.join(__dirname, process.platform === 'darwin' && process.arch === 'arm64' ? process.platform + process.arch : process.platform)
+var bin_path = path.join(
+  __dirname,
+  process.platform === "darwin" && process.arch === "arm64"
+    ? process.platform + process.arch
+    : process.platform
+);
 
 /**
  * @type{string}
@@ -172,6 +177,7 @@ Subcommands:
   clean
   format
   convert
+  dump
   help
 
 Run \`rescript <subcommand> -h\` for subcommand help. Examples:
@@ -185,7 +191,7 @@ function releaseBuild() {
   if (is_building) {
     try {
       fs.unlinkSync(lockFileName);
-    } catch (err) { }
+    } catch (err) {}
     is_building = false;
   }
 }
@@ -219,7 +225,7 @@ if (
   /**
    * @type {string}
    */
-  var bsc_exe = path.join(bin_path, "bsc.exe")
+  var bsc_exe = path.join(bin_path, "bsc.exe");
 
   switch (maybe_subcommand) {
     case "format":
@@ -229,6 +235,13 @@ if (
         bsc_exe
       );
       break;
+    case "dump":
+      require("./scripts/rescript_dump.js").main(
+        process.argv.slice(3),
+        bsb_exe,
+        bsc_exe
+      );
+      break;
     case "convert":
       // Todo
       require("./scripts/rescript_convert.js").main(

scripts/rescript_arg.js

@@ -36,18 +36,18 @@ function bad_arg(s) {
  */
 function usage_b(b, usage, specs) {
   b.add(usage);
-  b.add(`\nOptions:\n`);
-  if(specs.length === 0){
-    return
+  if (specs.length === 0) {
+    return;
   }
+  b.add(`\nOptions:\n`);
   var max_col = 0;
   for (let [key] of specs) {
     if (key.length > max_col) {
       max_col = key.length;
     }
   }
   for (let i = 0; i < specs.length; i++) {
-    let [key, _, doc] = specs[i]
+    let [key, _, doc] = specs[i];
     if (!doc.startsWith("*internal*")) {
       b.add("  ")
         .add(key)
@@ -86,7 +86,7 @@ function stop_raise(usage, error, specs) {
     case "Unknown":
       if (["-help", "--help", "-h"].includes(error.data)) {
         usage_b(b, usage, specs);
-        console.error(b.val);
+        process.stderr.write(b.val);
         process.exit(0);
       } else {
         b.add("unknown option: '").add(error.data).add("'.\n");
@@ -163,6 +163,6 @@ function parse_exn(
   }
   annofun(list);
 }
-
+exports.bad_arg = bad_arg;
 exports.parse_exn = parse_exn;
 exports.ArgError = ArgError;

scripts/rescript_dump.js

@@ -0,0 +1,57 @@
+//@ts-check
+var arg = require("./rescript_arg.js");
+var dump_usage = `Usage: rescript dump <options> [target]
+\`rescript dump\` dumps the information for the target
+`;
+var child_process = require("child_process");
+var path = require("path");
+var specs = [];
+
+/**
+ * @param {string[]} argv
+ * @param {string} bsb_exe
+ * @param {string} bsc_exe
+ */
+function main(argv, bsb_exe, bsc_exe) {
+  var target;
+  arg.parse_exn(dump_usage, argv, specs, (xs) => {
+    if (xs.length !== 1) {
+      arg.bad_arg(`Expect only one target, ${xs.length} found` );
+    }
+    target = xs[0];
+  });
+
+  var { ext } = path.parse(target);
+  if (ext !== ".cmi") {
+    console.error("Only .cmi target allowed");
+    process.exit(2);
+  }
+
+
+  var output = child_process.spawnSync(
+    bsb_exe,
+    ["build", "--", target],
+    {
+      encoding: "utf-8",
+    }
+  );
+  if (output.status !== 0) {
+    console.log(output.stdout);
+    console.error(output.stderr);
+    process.exit(2);
+  }
+  output = child_process.spawnSync(
+    bsc_exe,
+    [path.join("lib", "bs", target)],
+    {
+      encoding: "utf-8",
+    }
+  );
+  console.log(output.stdout.trimEnd());
+  if (output.status !== 0) {
+    console.error(output.stderr);
+    process.exit(2);
+  }
+}
+
+exports.main = main;