Textual approach can work

build.zig

@@ -4,26 +4,53 @@ pub fn build(b: *std.build.Builder) void {
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
 
-    const arocc_dep = b.anonymousDependency("arocc", @import("arocc/build.zig"), .{
-        .target = target,
-        .optimize = optimize,
-    });
+    const textual = true;
+    if (!textual) {
+        const arocc_dep = b.anonymousDependency("arocc", @import("arocc/build.zig"), .{
+            .target = target,
+            .optimize = optimize,
+        });
 
-    const exe = b.addExecutable(.{
-        .name = "universal-headers",
-        .root_source_file = .{ .path = "src/main.zig" },
-        .target = target,
-        .optimize = optimize,
-    });
-    exe.addModule("arocc", arocc_dep.module("aro"));
-    b.installArtifact(exe);
+        const exe = b.addExecutable(.{
+            .name = "universal-headers",
+            .root_source_file = .{ .path = "src/main.zig" },
+            .target = target,
+            .optimize = optimize,
+        });
+        exe.addModule("arocc", arocc_dep.module("aro"));
+        b.installArtifact(exe);
 
-    const run_cmd = b.addRunArtifact(exe);
-    run_cmd.step.dependOn(b.getInstallStep());
-    if (b.args) |args| {
-        run_cmd.addArgs(args);
-    }
+        const run_cmd = b.addRunArtifact(exe);
+        run_cmd.step.dependOn(b.getInstallStep());
+        if (b.args) |args| {
+            run_cmd.addArgs(args);
+        }
+
+        const run_step = b.step("run", "Run the app");
+        run_step.dependOn(&run_cmd.step);
+    } else {
+        const addHeaders = b.addExecutable(.{
+            .name = "addHeaders",
+            .root_source_file = .{ .path = "src/textdiff/addHeaders.zig" },
+            .target = target,
+            .optimize = optimize,
+        });
+        b.installArtifact(addHeaders);
 
-    const run_step = b.step("run", "Run the app");
-    run_step.dependOn(&run_cmd.step);
+        const outputHeaders = b.addExecutable(.{
+            .name = "outputHeaders",
+            .root_source_file = .{ .path = "src/textdiff/outputHeaders.zig" },
+            .target = target,
+            .optimize = optimize,
+        });
+        b.installArtifact(outputHeaders);
+
+        const testHeaders = b.addExecutable(.{
+            .name = "testHeaders",
+            .root_source_file = .{ .path = "src/textdiff/testHeaders.zig" },
+            .target = target,
+            .optimize = optimize,
+        });
+        b.installArtifact(testHeaders);
+    }
 }

src/textdiff/HOWTO.txt

@@ -0,0 +1,31 @@
+
+zig build
+- should give you (in zig-out/bin): addHeaders, outputHeaders, testHeaders
+- also shells out to diff
+
+
+for the whole thing, run (for me this takes ~30min):
+./src/textdiff/compile.bash headers/*
+
+then to test (takes ~5min):
+./src/textdiff/test.bash headers/*
+
+
+What's going on:
+
+1. addHeaders headers/foo
+- takes files from foo
+- normalizes them into uh_norm
+- for each file:
+    - adds context prefix to each line
+    - outputs to uh_workfile
+    - diffs with file in uh_workspace and modifies uh_workspace
+
+2. outputHeaders uh_headers
+- reads files from uh_workspace and outputs universal headers in uh_headers
+- uses reductions.zig to reduce #if statements
+
+3. testHeaders headers/foo
+- partially evaluates uh_headers for version foo and outputs to uh_test
+- can then diff uh_test uh_norm/foo
+