feat: semantics for if statements and multi-prong if statements

src/Ir.zig

@@ -24,6 +24,8 @@ pub const Inst = struct {
         decl_var,
         decl_ref,
         block,
+        condbr,
+        @"break",
         alloc_local,
         load_local,
         store_local,
@@ -33,11 +35,19 @@ pub const Inst = struct {
         div,
         mod,
         neg,
+        not,
+        cmp_eq,
+        cmp_neq,
+        cmp_gt,
+        cmp_gte,
+        cmp_lt,
+        cmp_lte,
         true_literal,
         false_literal,
         integer,
         string,
-        content,
+        content_push,
+        content_flush,
     };
 
     pub const Data = union {
@@ -45,11 +55,11 @@ pub const Inst = struct {
             payload_index: u32,
         },
         un: struct {
-            lhs: Inst.Index,
+            lhs: Index,
         },
         bin: struct {
-            lhs: Inst.Index,
-            rhs: Inst.Index,
+            lhs: Index,
+            rhs: Index,
         },
         integer: struct {
             value: u64,
@@ -66,7 +76,7 @@ pub const Inst = struct {
 
     pub const Declaration = struct {
         name: NullTerminatedString,
-        value: Inst.Index,
+        value: Index,
     };
 
     pub const Knot = struct {
@@ -80,6 +90,16 @@ pub const Inst = struct {
     pub const Block = struct {
         body_len: u32,
     };
+
+    pub const Break = struct {
+        block_inst: Index,
+    };
+
+    pub const CondBr = struct {
+        condition: Index,
+        then_body_len: u32,
+        else_body_len: u32,
+    };
 };
 
 pub const Global = struct {
@@ -112,29 +132,6 @@ pub fn deinit(ir: *Ir, gpa: std.mem.Allocator) void {
     ir.* = undefined;
 }
 
-const Prefix = struct {
-    buf: std.ArrayListUnmanaged(u8) = .empty,
-
-    pub fn deinit(self: *Prefix, gpa: std.mem.Allocator) void {
-        self.buf.deinit(gpa);
-    }
-
-    pub fn writeIndent(self: *const Prefix, writer: *std.Io.Writer) !void {
-        try writer.writeAll(self.buf.items);
-    }
-
-    pub fn pushChildPrefix(self: *Prefix, gpa: std.mem.Allocator) !usize {
-        const old_len = self.buf.items.len;
-        const seg: []const u8 = "   ";
-        try self.buf.appendSlice(gpa, seg);
-        return old_len;
-    }
-
-    pub fn restore(self: *Prefix, new_len: usize) void {
-        self.buf.shrinkRetainingCapacity(new_len);
-    }
-};
-
 const Render = struct {
     gpa: std.mem.Allocator,
     prefix: Prefix,
@@ -145,6 +142,29 @@ const Render = struct {
         WriteFailed,
     };
 
+    const Prefix = struct {
+        buf: std.ArrayListUnmanaged(u8) = .empty,
+
+        pub fn deinit(self: *Prefix, gpa: std.mem.Allocator) void {
+            self.buf.deinit(gpa);
+        }
+
+        pub fn writeIndent(self: *const Prefix, writer: *std.Io.Writer) !void {
+            try writer.writeAll(self.buf.items);
+        }
+
+        pub fn pushChildPrefix(self: *Prefix, gpa: std.mem.Allocator) !usize {
+            const old_len = self.buf.items.len;
+            const seg: []const u8 = "  ";
+            try self.buf.appendSlice(gpa, seg);
+            return old_len;
+        }
+
+        pub fn restore(self: *Prefix, new_len: usize) void {
+            self.buf.shrinkRetainingCapacity(new_len);
+        }
+    };
+
     fn renderSimple(r: *Render, inst: Inst) Error!void {
         const io_w = r.writer;
         return io_w.print("{s}(?)", .{@tagName(inst.tag)});
@@ -183,6 +203,26 @@ const Render = struct {
         try io_w.writeAll(")");
     }
 
+    fn renderBreak(r: *Render, ir: Ir, inst: Inst) Error!void {
+        const io_w = r.writer;
+        const extra = ir.extraData(Inst.Break, inst.data.payload.payload_index);
+
+        try io_w.print("{s}(%{d})", .{ @tagName(inst.tag), extra.data.block_inst });
+    }
+
+    fn renderCondbr(r: *Render, ir: Ir, inst: Inst) Error!void {
+        const io_w = r.writer;
+        const extra = ir.extraData(Inst.CondBr, inst.data.payload.payload_index);
+        const then_body = ir.bodySlice(extra.end, extra.data.then_body_len);
+        const else_body = ir.bodySlice(extra.end + then_body.len, extra.data.else_body_len);
+
+        try io_w.print("{s}(%{d}, ", .{ @tagName(inst.tag), extra.data.condition });
+        try renderBodyInner(r, ir, then_body);
+        try io_w.writeAll(", ");
+        try renderBodyInner(r, ir, else_body);
+        try io_w.writeAll(")");
+    }
+
     fn renderKnotDecl(r: *Render, ir: Ir, inst: Inst) Error!void {
         const io_w = r.writer;
         const extra = ir.extraData(Inst.Knot, inst.data.payload.payload_index);
@@ -244,6 +284,8 @@ const Render = struct {
                 const str_bytes = inst.data.string.get(ir);
                 try io_w.print("{s}(\"{s}\")", .{ @tagName(inst.tag), str_bytes });
             },
+            .condbr => try r.renderCondbr(ir, inst),
+            .@"break" => try r.renderBreak(ir, inst),
             .alloc_local => try r.renderSimple(inst),
             .load_local => try r.renderUnary(inst),
             .store_local => try r.renderBinary(inst),
@@ -254,6 +296,13 @@ const Render = struct {
             .div => try r.renderBinary(inst),
             .mod => try r.renderBinary(inst),
             .neg => try r.renderUnary(inst),
+            .not => try r.renderUnary(inst),
+            .cmp_eq => try r.renderBinary(inst),
+            .cmp_neq => try r.renderBinary(inst),
+            .cmp_gt => try r.renderBinary(inst),
+            .cmp_gte => try r.renderBinary(inst),
+            .cmp_lt => try r.renderBinary(inst),
+            .cmp_lte => try r.renderBinary(inst),
             .true_literal => {
                 try io_w.print("{s}", .{@tagName(inst.tag)});
             },
@@ -268,7 +317,8 @@ const Render = struct {
                 const str_bytes = inst.data.string.get(ir);
                 try io_w.print("{s}(\"{s}\")", .{ @tagName(inst.tag), str_bytes });
             },
-            .content => try r.renderUnary(inst),
+            .content_push => try r.renderSimple(inst),
+            .content_flush => try r.renderUnary(inst),
         }
         try io_w.writeAll("\n");
     }