From a088f97e2e799b556f954a09ab6a4db4d0e0776a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mikael=20L=C3=B6vqvist?= <mikael.lovqvist.mail@gmail.com>
Date: Wed, 8 Apr 2026 23:32:05 +0200
Subject: [PATCH] Started textnodes, renamed tool with wrong name, started
 field configuration system

---
 experiments/config.mjs                        | 16 +++++++++++++
 experiments/package.json                      |  3 ++-
 experiments/textnodes.mjs                     |  0
 package-manifest.yaml                         |  6 +++++
 source/data/field-configuration.mjs           | 24 +++++++++++++++++++
 source/errors.mjs                             | 13 ++++++++++
 ...{stage-for-pnpn.mjs => stage-for-pnpm.mjs} |  2 +-
 7 files changed, 62 insertions(+), 2 deletions(-)
 create mode 100644 experiments/config.mjs
 create mode 100644 experiments/textnodes.mjs
 create mode 100644 source/data/field-configuration.mjs
 rename tools/{stage-for-pnpn.mjs => stage-for-pnpm.mjs} (98%)

diff --git a/experiments/config.mjs b/experiments/config.mjs
new file mode 100644
index 0000000..2da6ad8
--- /dev/null
+++ b/experiments/config.mjs
@@ -0,0 +1,16 @@
+import { Field_Configuration  } from '@efforting.tech/data/field-configuration';
+
+
+function mandatory_anything(value) {
+	return value !== undefined;
+}
+
+
+const fc = new Field_Configuration('Some_Field', mandatory_anything, 'Anything defined');
+
+
+console.log(fc.check_validation(undefined));
+console.log(fc.check_validation(true));
+
+//fc.validate(undefined);
+fc.validate(undefined, 'New thingamabob object');
diff --git a/experiments/package.json b/experiments/package.json
index cfc1bee..e7e513a 100644
--- a/experiments/package.json
+++ b/experiments/package.json
@@ -3,6 +3,7 @@
 	"type": "module",
 	"dependencies": {
 		"@efforting.tech/errors": "link:../build/packages/errors",
-		"@efforting.tech/rule-processing": "link:../build/packages/rule-processing"
+		"@efforting.tech/rule-processing": "link:../build/packages/rule-processing",
+		"@efforting.tech/data": "link:../build/packages/data"
 	}
 }
\ No newline at end of file
diff --git a/experiments/textnodes.mjs b/experiments/textnodes.mjs
new file mode 100644
index 0000000..e69de29
diff --git a/package-manifest.yaml b/package-manifest.yaml
index 5cb54ac..f225fdc 100644
--- a/package-manifest.yaml
+++ b/package-manifest.yaml
@@ -21,6 +21,12 @@ packages:
     internal-dependencies:
       - errors
 
+  data:
+    path: source/data
+    #documentation: documentation/data
+    description: Data management
+    internal-dependencies:
+      - errors
 
 wip-packages:
   object-graph-storage:
diff --git a/source/data/field-configuration.mjs b/source/data/field-configuration.mjs
new file mode 100644
index 0000000..9516d28
--- /dev/null
+++ b/source/data/field-configuration.mjs
@@ -0,0 +1,24 @@
+import { Invalid_Data } from '@efforting.tech/errors';
+
+export class Field_Configuration {
+	constructor(name, validator=null, expected=undefined) {
+		Object.assign(this, { name, validator, expected });
+	}
+
+	check_validation(value) {
+		const { validator } = this;
+
+		return !validator || validator(value);
+	}
+
+	validate(value, target=undefined) {
+		const { validator, name, expected } = this;
+		if (!this.check_validation(value)) {
+			throw new Invalid_Data({
+				name, validator, value,
+				target, expected,
+			});
+		}
+	}
+
+}
diff --git a/source/errors.mjs b/source/errors.mjs
index 98d6a00..37622b0 100644
--- a/source/errors.mjs
+++ b/source/errors.mjs
@@ -1,5 +1,18 @@
 import { inspect } from 'node:util';
 
+// § GROUP: Configuration field errors
+
+export class Invalid_Data extends Error {
+	constructor(data) {
+		const { value, target, expected, validator, name } = data;
+		const type = value === null ? 'null' : typeof value;
+		const target_info = target ? inspect(target) : 'unknown target';
+		const expected_desc = expected ?? `data that would pass validation using ${validator}`;
+		super(`Data validation failed for field "${name}" of ${target_info}. Encountered data of type "${type}" while expecting "${expected_desc}".`);
+		this.data = data;
+	}
+}
+
 // § GROUP: Resolving errors
 
 export class Item_Unresolvable extends Error {
diff --git a/tools/stage-for-pnpn.mjs b/tools/stage-for-pnpm.mjs
similarity index 98%
rename from tools/stage-for-pnpn.mjs
rename to tools/stage-for-pnpm.mjs
index eba2b3a..20ec7af 100644
--- a/tools/stage-for-pnpn.mjs
+++ b/tools/stage-for-pnpm.mjs
@@ -89,7 +89,7 @@ for (const [package_name, package_data] of Object.entries(manifest.packages)) {
 	const exports_map = {};
 	for (const file of linked_sources) {
 		const name = path.basename(file, '.mjs');
-		const key = name === pkg.name ? '.' : `./${name}`;
+		const key = name === path.basename(pkg.name) ? '.' : `./${name}`;
 		exports_map[key] =  `./${file}`;
 	}