Added assert keyword, with re-routable print and assert outputs

source/compiler.c

@@ -29,6 +29,8 @@ void writeCompiler(Compiler* compiler, Node* node) {
 
 	//determine node type
 	switch(node->type) {
+		//TODO: more types, like variables, etc.
+
 		case NODE_LITERAL: {
 			//ensure the literal is in the cache
 			int index = findLiteralIndex(&compiler->literalCache, node->atomic.literal);

source/interpreter.c

@@ -6,6 +6,17 @@
 #include <stdio.h>
 #include <string.h>
 
+static void stdoutWrapper(const char* output) {
+	fprintf(stdout, output);
+	fprintf(stdout, "\n"); //default new line
+}
+
+static void stderrWrapper(const char* output) {
+	fprintf(stderr, "Assertion failure: ");
+	fprintf(stderr, output);
+	fprintf(stderr, "\n"); //default new line
+}
+
 void initInterpreter(Interpreter* interpreter, unsigned char* bytecode, int length) {
 	initLiteralArray(&interpreter->literalCache);
 	interpreter->bytecode = bytecode;
@@ -13,6 +24,9 @@ void initInterpreter(Interpreter* interpreter, unsigned char* bytecode, int leng
 	interpreter->count = 0;
 
 	initLiteralArray(&interpreter->stack);
+
+	setInterpreterPrint(interpreter, stdoutWrapper);
+	setInterpreterAssert(interpreter, stderrWrapper);
 }
 
 void freeInterpreter(Interpreter* interpreter) {
@@ -21,6 +35,15 @@ void freeInterpreter(Interpreter* interpreter) {
 	freeLiteralArray(&interpreter->stack);
 }
 
+//utilities for the host program
+void setInterpreterPrint(Interpreter* interpreter, PrintFn printOutput) {
+	interpreter->printOutput = printOutput;
+}
+
+void setInterpreterAssert(Interpreter* interpreter, PrintFn assertOutput) {
+	interpreter->assertOutput = assertOutput;
+}
+
 //utils
 static unsigned char readByte(unsigned char* tb, int* count) {
 	unsigned char ret = *(unsigned char*)(tb + *count);
@@ -67,12 +90,30 @@ static void consumeShort(unsigned short bytes, unsigned char* tb, int* count) {
 }
 
 //each available statement
+static bool execAssert(Interpreter* interpreter) {
+	Literal rhs = popLiteralArray(&interpreter->stack);
+	Literal lhs = popLiteralArray(&interpreter->stack);
+
+	if (!IS_STRING(rhs)) {
+		printf("[internal] The interpreter's assert keyword needs a string as the second argument, received: ");
+		printLiteral(rhs);
+		printf("\n");
+		return false;
+	}
+
+	if (!IS_TRUTHY(lhs)) {
+		(*interpreter->assertOutput)(AS_STRING(rhs));
+		return false;
+	}
+
+	return true;
+}
+
 static bool execPrint(Interpreter* interpreter) {
 	//print what is on top of the stack, then pop it
 	Literal lit = popLiteralArray(&interpreter->stack);
 
-	printLiteral(lit);
+	printLiteralCustom(lit, interpreter->printOutput);
-	printf("\n");
 
 	freeLiteral(lit);
 
@@ -193,6 +234,12 @@ static void execInterpreter(Interpreter* interpreter) {
 
 	while(opcode != OP_EOF && opcode != OP_SECTION_END) {
 		switch(opcode) {
+			case OP_ASSERT:
+				if (!execAssert(interpreter)) {
+					return;
+				}
+			break;
+
 			case OP_PRINT:
 				if (!execPrint(interpreter)) {
 					return;

source/interpreter.h

@@ -4,17 +4,24 @@
 
 #include "literal_array.h"
 
+typedef void (*PrintFn)(const char*);
+
 //the interpreter acts depending on the bytecode instructions
 typedef struct Interpreter {
 	LiteralArray literalCache; //generally doesn't change after initialization
 	unsigned char* bytecode;
 	int length;
 	int count;
-
 	LiteralArray stack;
+	PrintFn printOutput;
+	PrintFn assertOutput;
 } Interpreter;
 
 void initInterpreter(Interpreter* interpreter, unsigned char* bytecode, int length);
 void freeInterpreter(Interpreter* interpreter);
 
+//utilities for the host program
+void setInterpreterPrint(Interpreter* interpreter, PrintFn printOutput);
+void setInterpreterAssert(Interpreter* interpreter, PrintFn assertOutput);
+
 void runInterpreter(Interpreter* interpreter);

source/literal.c

@@ -4,26 +4,43 @@
 #include <stdio.h>
 #include <string.h>
 
+static void stdoutWrapper(const char* output) {
+	fprintf(stdout, output);
+}
+
 void printLiteral(Literal literal) {
+	printLiteralCustom(literal, stdoutWrapper);
+}
+
+void printLiteralCustom(Literal literal, void (printFn)(const char*)) {
 	switch(literal.type) {
 		case LITERAL_NULL:
-			printf("null");
+			printFn("null");
 		break;
 
 		case LITERAL_BOOLEAN:
-			printf(AS_BOOLEAN(literal) ? "true" : "false");
+			printFn(AS_BOOLEAN(literal) ? "true" : "false");
 		break;
 
-		case LITERAL_INTEGER:
+		case LITERAL_INTEGER: {
-			printf("%d", AS_INTEGER(literal));
+			char buffer[256];
+			snprintf(buffer, 256, "%d", AS_INTEGER(literal));
+			printFn(buffer);
+		}
 		break;
 
-		case LITERAL_FLOAT:
+		case LITERAL_FLOAT: {
-			printf("%g", AS_FLOAT(literal));
+			char buffer[256];
+			snprintf(buffer, 256, "%g", AS_FLOAT(literal));
+			printFn(buffer);
+		}
 		break;
 
-		case LITERAL_STRING:
+		case LITERAL_STRING: {
-			printf("%.*s", STRLEN(literal), AS_STRING(literal));
+			char buffer[256];
+			snprintf(buffer, 256, "%.*s", STRLEN(literal), AS_STRING(literal));
+			printFn(buffer);
+		}
 		break;
 
 		default:

source/literal.h

@@ -60,6 +60,7 @@ typedef struct {
 // #define TO_FUNCTION_PTR(value)		((Literal){LITERAL_FUNCTION,	{ .function = (Function*)value }})
 
 void printLiteral(Literal literal);
+void printLiteralCustom(Literal literal, void (printFn)(const char*));
 void freeLiteral(Literal literal);
 
 #define IS_TRUTHY(x) _isTruthy(x)

source/opcodes.h

@@ -3,7 +3,8 @@
 typedef enum Opcode {
 	OP_EOF,
 
-	//basic operations
+	//basic statements
+	OP_ASSERT,
 	OP_PRINT,
 
 	//data

source/parser.c

@@ -486,8 +486,6 @@ static void expression(Parser* parser, Node** nodeHandle) {
 
 //statements
 static void printStmt(Parser* parser, Node* node) {
-	int line = parser->previous.line;
-	
 	//set the node info
 	node->type = NODE_UNARY;
 	node->unary.opcode = OP_PRINT;
@@ -496,6 +494,18 @@ static void printStmt(Parser* parser, Node* node) {
 	consume(parser, TOKEN_SEMICOLON, "Expected ';' at end of print statement");
 }
 
+static void assertStmt(Parser* parser, Node* node) {
+	//set the node info
+	node->type = NODE_BINARY;
+	node->unary.opcode = OP_ASSERT;
+
+	expression(parser, &(node->binary.left));
+	consume(parser, TOKEN_COMMA, "Expected ',' in assert statement");
+	expression(parser, &(node->binary.right));
+
+	consume(parser, TOKEN_SEMICOLON, "Expected ';' at end of assert statement");
+}
+
 //precedence functions
 static void expressionStmt(Parser* parser, Node* node) {
 	error(parser, parser->previous, "Expression statements not yet implemented");
@@ -508,6 +518,12 @@ static void statement(Parser* parser, Node* node) {
 		return;
 	}
 
+	//assert
+	if (match(parser, TOKEN_ASSERT)) {
+		assertStmt(parser, node);
+		return;
+	}
+
 	//default
 	expressionStmt(parser, node);
 }