add identifiers, procedure calls and a built in print procedure

1 files changed, 26 insertions, 1 deletions

diff --git a/src/compile.zig b/src/compile.zig
index 2bf404d..9d70a58 100644
--- a/src/compile.zig
+++ b/src/compile.zig
@@ -14,6 +14,7 @@ pub const Instr = struct {
     pub const Type = union(enum) {
         constant: Constant,
         bin_op: BinOp,
+        print: Print,
     };
 
     pub const Constant = struct {
@@ -41,15 +42,24 @@ pub const Instr = struct {
         }
     };
 
+    pub const Print = struct {
+        arg: VReg,
+
+        pub fn sources(self: Print) Sources {
+            return Sources.fromSlice(&.{self.arg}) catch unreachable;
+        }
+    };
+
     pub fn sources(self: Instr) Sources {
         return switch (self.type) {
             inline else => |instr| instr.sources(),
         };
     }
 
-    pub fn dest(self: *const Instr) VReg {
+    pub fn dest(self: *const Instr) ?VReg {
         return switch (self.type) {
             inline .constant, .bin_op => |s| s.dest,
+            inline .print => null,
         };
     }
 
@@ -123,6 +133,21 @@ const CompileContext = struct {
                     },
                 });
             },
+            .call => |call| {
+                if (call.proc.type == .identifier and
+                    std.mem.eql(u8, call.proc.loc.getIdent(self.source), "print"))
+                {
+                    const arg = try self.compileExpr(call.arg);
+                    try self.addInstr(.{
+                        .loc = expr.loc,
+                        .type = .{ .print = .{ .arg = arg } },
+                    });
+                    // BUG: we're returning a bogus virtual register that we didn't write to
+                } else {
+                    return error.CantCallAnythingButPrint;
+                }
+            },
+            .identifier => return error.CantCompileIdentifierExpr,
             .invalid => return error.CantCompileInvalidExpr,
         }
         return dest;