feat(engines) implement placeholder templating within texts

src/Utils/Placekeeper.js

@@ -0,0 +1,96 @@
+export default class Placekeeper {
+	static KEYWORDS = ['if', 'for', 'while', 'else', 'elseif', 'end'];
+	static init(content) {
+		const sections = Array();
+		const variables = new Map();
+		const currentSection = new Map();
+
+		for (let idx = 0; idx < content.length; idx++) {
+			const char = content[idx];
+			if (char == '{') {
+				if (content[idx + 1] == '{') {
+					if (currentSection.has('start')) currentSection.clear(); // everything before this was not a section then
+					// begins a new section meant to be for a variable but still can be an operational section
+					// @example: {{#if variableName}} {{#for variableName}} {{#while variableName}}
+					currentSection.set('start', idx);
+				}
+			} else if (currentSection.has('start')) {
+				if (char == '}') {
+					if (content[idx + 1] == '}') {
+						// ends a section
+						currentSection.set('end', idx + 2);
+						currentSection.set(
+							'content',
+							content
+								.substring(
+									currentSection.get('start'),
+									currentSection.get('end')
+								)
+								.toString()
+								.trim()
+						);
+
+						currentSection.set(
+							'variables',
+							Placekeeper.parseVariables(
+								currentSection.get('content')
+							)
+						);
+						sections.push(new Map(currentSection));
+						currentSection.clear();
+						for (const [key, value] of sectionVars) {
+							variables.set(key, value);
+						}
+						idx++;
+					}
+				}
+			}
+		}
+		console.log(sections);
+		return {
+			variables,
+			sections,
+		};
+	}
+
+	static parseVariables(content) {
+		// iterates over the content character by character to extract variables and returns a list of them
+		const variables = new Map();
+		let currentVar;
+
+		for (let idx = 0; idx < content.length; idx++) {
+			const char = content[idx];
+			if (char.matches(/[\w\d]/)) {
+				if (!currentVar instanceof Map)
+					currentVar = new Map([
+						['name', ''],
+						['start', idx],
+						['end', -1],
+					]);
+				currentVar.set('name', currentVar.get('name') + char);
+			}
+		}
+	}
+
+	static parse(content, sections) {
+		// replace all sections with an empty string
+		if (!Array.isArray(sections)) {
+			if (!sections instanceof Map) return content;
+			sections = [...sections.values()];
+		}
+
+		let parts = [];
+		let offset = 0;
+		for (const section of sections) {
+			if (!section instanceof Map) {
+				if (!Array.isArray(section)) continue;
+				if (section.length < 3) continue;
+			}
+			parts.push(content.substring(offset, section.get('start')));
+			offset = section.get('end');
+		}
+		parts.push(content.substring(offset));
+
+		return parts.join('');
+	}
+}