add draft impl for ampCmd

examples/middle_echo.scri

@@ -1,3 +1,4 @@
 load :0;
-echo 3 0 1 0.2;
+amp 10 1;
+# echo 3 0 1 0.2;
 quicksave;

src/lang.zig

@@ -19,6 +19,16 @@ pub const Command = struct {
     pub fn print(self: *const Command) void {
         std.debug.warn("cmd:{}\n", self.command);
     }
+
+    pub fn intArgAt(self: *const Command, idx: usize) !i32 {
+        var arg = self.args.at(idx);
+        return try std.fmt.parseInt(i32, arg, 10);
+    }
+
+    pub fn floatArgAt(self: *const Command, idx: usize) !f32 {
+        var arg = self.args.at(idx);
+        return try std.fmt.parseFloat(f32, arg);
+    }
 };
 
 pub const CommandList = std.ArrayList(*Command);

src/plugin.zig

@@ -0,0 +1,17 @@
+const std = @import("std");
+
+/// Control port
+pub const Param = struct {
+    /// Port symbol
+    sym: []const u8,
+
+    /// Control value
+    value: f32,
+};
+
+pub const ParamList = std.ArrayList(Param);
+
+pub const Position = struct {
+    split: usize,
+    index: usize,
+};

src/runner.zig

@@ -1,6 +1,7 @@
 const std = @import("std");
 const lang = @import("lang.zig");
 const images = @import("image.zig");
+const plugin = @import("plugin.zig");
 
 const Image = images.Image;
 
@@ -70,6 +71,8 @@ pub const Runner = struct {
             return RunError.NoBMP;
         }
 
+        // TODO, copy load_path into a temporary file, then use that
+        // file to work on things.
         self.image = try Image.open(self.allocator, load_path);
     }
 
@@ -135,6 +138,24 @@ pub const Runner = struct {
         std.debug.warn("out path: {}\n", out_path);
     }
 
+    /// Run the http://lv2plug.in/plugins/eg-amp plugin over the file.
+    fn ampCmd(self: *Runner, split: i32, index: i32, gain: f32) !void {
+        var param = try self.allocator.create(plugin.Param);
+        defer self.allocator.destroy(param);
+
+        param.* = Param{ .sym = "gain", .value = gain };
+
+        var params = plugin.ParamList.init(self.allocator);
+        defer params.deinit();
+
+        // TODO impl this
+        try image.runPlugin(
+            "http://lv2plug.in/plugins/eg-amp",
+            plugin.Position{ .split = split, .index = index },
+            params,
+        );
+    }
+
     fn runCommand(self: *Runner, cmd: *lang.Command) !void {
         return switch (cmd.command) {
             .Noop => {},
@@ -143,8 +164,15 @@ pub const Runner = struct {
                 try self.loadCmd(path);
                 break :blk;
             },
-
             .Quicksave => try self.quicksaveCmd(),
+
+            // .Amp => blk: {
+            //     const split = try cmd.intArgAt(0);
+            //     const index = try cmd.intArgAt(1);
+            //     const gain = try cmd.floatArgAt(2);
+            //     try self.ampCmd(split, index, gain);
+            // }
+
             else => blk: {
                 std.debug.warn("Unknown command: {}\n", cmd.command);
                 break :blk RunError.UnknownCommand;