Start of template runner

Author: MitMaro

src/Runner.js

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+'use strict';
+
+const RuntimeError = require('./error/Runtime');
+
+const {
+	OPERATOR_EQUALS,
+	OPERATOR_NOT_EQUALS,
+	OPERATOR_STRICT_EQUALS,
+	OPERATOR_STRICT_NOT_EQUALS,
+	OPERATOR_AND,
+	OPERATOR_OR,
+	OPERATOR_NOT,
+	OPERATOR_GREATER_THAN,
+	OPERATOR_LESS_THAN,
+	OPERATOR_GREATER_EQUAL_THAN,
+	OPERATOR_LESS_EQUAL_THAN,
+
+	PARSER_TYPE_ROOT,
+	PARSER_TYPE_TEXT_LITERAL,
+	PARSER_TYPE_INCLUDE,
+	PARSER_TYPE_VALUE,
+	PARSER_TYPE_VARIABLE,
+	PARSER_TYPE_BRANCH,
+	PARSER_TYPE_UNARY_OPERATOR,
+	PARSER_TYPE_BINARY_OPERATOR
+} = require('./constants');
+
+class Runner {
+	constructor(ast, input) {
+		this.ast = ast;
+		this.input = input;
+		this.result = [];
+	}
+
+	invoke() {
+		this.invokeRoot(this.ast);
+	}
+
+	invokeRoot(ast) {
+		for (const statement in ast.statements) {
+			if (statement.type === PARSER_TYPE_TEXT_LITERAL) {
+				this.result.push(statement.value);
+			}
+			else if (statement.type === PARSER_TYPE_INCLUDE) {
+				this.invokeInclude(statement);
+			}
+			else (statement.type === PARSER_TYPE_BRANCH) {
+				this.invokeBranch(statement);
+			}
+		}
+	}
+
+	invokeInclude(statement) {
+		const path = statement.value;
+
+		if (typeof path !== string) {
+			throw new RuntimeError('Non string type passed to include.')
+		}
+		// TODO: include other file
+	}
+
+	invokeBranch(statement) {
+		for (const branch of statement.branches) {
+			if (this.evaluateExpression(branch.condition)) {
+
+			}
+		}
+	}
+
+	evaluateExpression(expression) {
+		if (expression.type === PARSER_TYPE_BINARY_OPERATOR) {
+			return this.evaluateBinaryExpression(expression);
+		}
+		else if (expression.type === PARSER_TYPE_UNARY_OPERATOR) {
+			return this.evaluateUnaryExpression(expression);
+		}
+		else if (expression.type === PARSER_TYPE_VALUE) {
+			return expression.value;
+		}
+		else if (expression.type === PARSER_TYPE_VARIABLE) {
+			return this.getValueFromVariable(expression.value);
+		}
+	}
+
+	evaluateBinaryExpression(expression) {
+		if (expression.operator === OPERATOR_EQUALS) {
+			return this.evaluateExpression(expression.left) == this.evaluateExpression(expression.right);
+		}
+
+		if (expression.operator === OPERATOR_NOT_EQUALS) {
+			return this.evaluateExpression(expression.left) != this.evaluateExpression(expression.right);
+		}
+
+		if (expression.operator === OPERATOR_STRICT_EQUALS) {
+			return this.evaluateExpression(expression.left) === this.evaluateExpression(expression.right);
+		}
+
+		if (expression.operator === OPERATOR_STRICT_NOT_EQUALS) {
+			return this.evaluateExpression(expression.left) !== this.evaluateExpression(expression.right);
+		}
+
+		if (expression.operator === OPERATOR_AND) {
+			return this.evaluateExpression(expression.left) && this.evaluateExpression(expression.right);
+		}
+
+		if (expression.operator === OPERATOR_OR) {
+			return this.evaluateExpression(expression.left) || this.evaluateExpression(expression.right);
+		}
+
+		throw new RuntimeError(`Unknown operator: ${expression.operator}`);
+	}
+
+	evaluateUnaryExpression(expression) {
+		if (expression.operator === OPERATOR_NOT) {
+			return !this.evaluateExpression(expression.expression);
+		}
+
+		throw new RuntimeError(`Unknown operator: ${expression.operator}`);
+	}
+
+	getValueFromVariable(name) {
+		if (!name in this.input) {
+			throw new RuntimeError(`Unset variable: ${name}`);
+		}
+		return this.input[name];
+	}
+
+}

src/error/Runtime.js

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+'use strict';
+
+const GeneralError = require('./General');
+
+class RuntimeError extends GeneralError {
+	constructor(message, statement) {
+		super(message);
+		this.statement = statement;
+	}
+}
+
+module.exports = RuntimeError;