swisseph_zig - Zig interface binding for the Swiss Ephemeris C library

Installation

Follow these steps to set up the Swiss Ephemeris library with your Zig project:

1. Clone the official swisseph repository:

   git clone https://github.com/aloistr/swisseph.git

2. Build it as a static library:

   cd swisseph
   make libswe.a

3. In the root of your project, create a directory called swisseph:

   mkdir -p path/to/your_project/swisseph

4. Copy the following files to your project:

   cp path/to/swisseph/libswe.a path/to/your_project/swisseph
   cp path/to/swisseph/swephexp.h path/to/your_project/swisseph
   cp path/to/swisseph/sweodef.h path/to/your_project/swisseph

5. Add swisseph_zig as a dependency in your build.zig.zon file:

    zig fetch --save git+https://github.com/gabrielvincent/swisseph_zig

6. Add swisseph_zig as module for your executable in build.zig:

   const exe = b.addExecutable(.{
       .name = "your_project",
       .root_source_file = b.path("src/main.zig"),
       .target = target,
       .optimize = optimize,
   });
   
   const swisseph_dir_opt = b.option(
       []const u8,
       "swisseph-dir",
       "Path to Swiss Ephemeris files (libswe.a, swephexp.h, sweodef.h)",
   ) orelse "swisseph";
   
   // Get the swisseph_zig dependency, passing the option to it
   const sweph_dep = b.dependency("swisseph_zig", .{
       .target = target,
       .optimize = optimize,
       .swisseph_dir = swisseph_dir_opt,
   });
   
   const sweph_mod = sweph_dep.module("swisseph_zig");
   sweph_mod.addIncludePath(b.path(swisseph_dir_opt));
   sweph_mod.addObjectFile(b.path(b.fmt("{s}/libswe.a", .{swisseph_dir_opt})));
   
   exe.root_module.addImport("swisseph_zig", sweph_dep.module("swisseph_zig"));

Usage

Here's a simple example of how to use the library in your Zig code:

const std = @import("std");
const sweph = @import("swisseph_zig");

pub fn main() !void {
    const jd: f64 = 2449090.1145833;
    var diags: Diagnostics = undefined;
    const eph = sweph.calc(jd, sweph.defs.SE_SUN, sweph.defs.SEFLG_SPEED | sweph.defs.SEFLG_JPLEPH, &diags) catch |err| {
        std.debug.print("calculation failed ({}). error message: {s}\n", .{err}, .{diags.err});
    };
}