add identifiers, procedure calls and a built in print procedure

1 files changed, 28 insertions, 2 deletions

diff --git a/src/parse.zig b/src/parse.zig
index 7daa3f8..d5d3e9b 100644
--- a/src/parse.zig
+++ b/src/parse.zig
@@ -15,6 +15,8 @@ pub const Expr = struct {
         integer_literal,
         bin_op: BinOp,
         invalid: Token,
+        call: Call,
+        identifier,
 
         pub const BinOp = struct {
             lhs: *const Expr,
@@ -35,6 +37,11 @@ pub const Expr = struct {
                 }
             };
         };
+
+        pub const Call = struct {
+            proc: *const Expr,
+            arg: *const Expr,
+        };
     };
 
     pub fn format(self: Expr, comptime fmt: []const u8, options: std.fmt.FormatOptions, writer: anytype) !void {
@@ -44,6 +51,8 @@ pub const Expr = struct {
             .integer_literal => try writer.print("<int>", .{}),
             .bin_op => |bin_op| try writer.print("({} {} {})", .{ bin_op.lhs, bin_op.op, bin_op.rhs }),
             .invalid => try writer.print("<invalid>", .{}),
+            .call => |call| try writer.print("({} {})", .{ call.proc, call.arg }),
+            .identifier => try writer.print("<identifier>", .{}),
         }
     }
 };
@@ -53,7 +62,7 @@ pub fn expression(allocator: Allocator, lexer: *Peekable(Lexer)) error{OutOfMemo
 }
 
 pub fn addExpr(allocator: Allocator, lexer: *Peekable(Lexer)) !*Expr {
-    var lhs = try primaryExpr(allocator, lexer);
+    var lhs = try callExpr(allocator, lexer);
     while (true) {
         const token: Lexer.Token = if (lexer.peek()) |t| t else break;
         const op: Expr.Type.BinOp.Op = switch (token.type) {
@@ -64,7 +73,7 @@ pub fn addExpr(allocator: Allocator, lexer: *Peekable(Lexer)) !*Expr {
 
         _ = lexer.next();
 
-        const rhs = try primaryExpr(allocator, lexer);
+        const rhs = try callExpr(allocator, lexer);
         lhs = try allocate(allocator, .{
             .loc = lhs.loc.combine(rhs.loc),
             .type = .{ .bin_op = .{ .lhs = lhs, .op = op, .rhs = rhs } },
@@ -73,6 +82,22 @@ pub fn addExpr(allocator: Allocator, lexer: *Peekable(Lexer)) !*Expr {
     return lhs;
 }
 
+pub fn callExpr(allocator: Allocator, lexer: *Peekable(Lexer)) !*Expr {
+    var proc = try primaryExpr(allocator, lexer);
+    while (true) {
+        switch (lexer.peek().?.type) {
+            .left_paren, .integer_literal => {},
+            else => break,
+        }
+        const arg = try primaryExpr(allocator, lexer);
+        proc = try allocate(allocator, .{
+            .loc = proc.loc.combine(arg.loc),
+            .type = .{ .call = .{ .proc = proc, .arg = arg } },
+        });
+    }
+    return proc;
+}
+
 pub fn primaryExpr(allocator: Allocator, lexer: *Peekable(Lexer)) !*Expr {
     const token = lexer.next().?;
     // std.debug.print("term {}\n", .{token});
@@ -88,6 +113,7 @@ pub fn primaryExpr(allocator: Allocator, lexer: *Peekable(Lexer)) !*Expr {
             return res;
         },
         .integer_literal => .{ .loc = token.loc, .type = .integer_literal },
+        .identifier => .{ .loc = token.loc, .type = .identifier },
         else => .{ .loc = token.loc, .type = .{ .invalid = token } },
     });
 }