feat: lower typed programs and interpret IR

std/io/io.hon

@@ -392,7 +392,7 @@ write_float proc($T type, output Writer, value T, scientific bool) void ! WriteE
     match typeinfo!(T) {
         .float: {
             buffer [64]mut u8 := undefined
-            count := 0
+            count c_int := 0
             if sizeof!(T) == 4 {
                 if (scientific) count = c.snprintf(ptrcast!((&buffer).ptr), c_ulong(buffer.len), "%.8e", value)
                 else count = c.snprintf(ptrcast!((&buffer).ptr), c_ulong(buffer.len), "%.9g", value)

std/process/arguments.hon

@@ -0,0 +1,16 @@
+# the bootstrap Init currently exposes only io; macOS provides process-lifetime argv storage.
+@hide:file
+_NSGetArgc c_func() @c_int
+
+@hide:file
+_NSGetArgv c_func() @*[*;0]u8
+
+argument_count proc() usize {
+    return usize(_NSGetArgc()^)
+}
+
+#! returns a borrowed, zero-terminated argument; storage lasts for the process lifetime.
+argument proc(index usize) ?[*;0]u8 {
+    if (index >= argument_count()) return null
+    return _NSGetArgv()^[index]
+}