G2Basic API

G2Basic is a small BASIC interpreter written in C for microcontrollers and other embedded hosts. A host program passes it one line at a time: numbered lines build a stored program, and other lines run immediately. This reference covers the public header g2basic.h and the internal backend hook. The source is on GitHub.

Guides

Guide	Contents
Language reference	Statements, expressions, commands, and limits
Embedding	CMake integration, output, custom functions, and the API contract
Architecture	Parser, program store, execution, and memory
Development	Builds, options, tests, CI, and API documentation
C coding standard	Style, memory, error handling, and documentation rules
Versioning	SemVer rules, the public interface, and the changelog

API groups

Group	Contents	Header
Embedding API	Setup and output, Custom functions, Execution	g2basic.h
Internal interfaces	Built-in function backends	g2basic_math.h

The group tree is on the Topics page. The Examples page contains the interactive interpreter, a complete host program.

Minimal host

#include <stdio.h>
#include "g2basic.h"
 
static void print_text(const char* text) {
    fputs(text, stdout);
}
 
int main(void) {
    double result;
    const char* error = NULL;
 
    g2basic_init(print_text);
    g2basic_parse("10 FOR I = 1 TO 3", &result, &error);
    g2basic_parse("20 PRINT I, I * I", &result, &error);
    g2basic_parse("30 NEXT I", &result, &error);
    g2basic_parse("RUN", &result, &error);  // 1 1, 2 4, 3 9
    return 0;
}