Tigerインタプリタで -1 や -x を扱えるようにしたい

code:diff

diff --git a/lib/parser.mly b/lib/parser.mly

index 32f4a41..5405e28 100644

--- a/lib/parser.mly

+++ b/lib/parser.mly

@@ -53,6 +53,7 @@ exp:

| exp LE exp { Syntax.OpExp { left = $1; op = Syntax.LeOp; right = $3} }

| exp GT exp { Syntax.OpExp { left = $1; op = Syntax.GtOp; right = $3} }

| exp GE exp { Syntax.OpExp { left = $1; op = Syntax.GeOp; right = $3} }

+| MINUS exp { Syntax.OpExp { left = Syntax.IntExp(0); op = Syntax.MinusOp; right = $2} }

| LET decs IN exp END { Syntax.LetExp { decs = $2; body = $4 } }

| ID LPAREN args RPAREN { Syntax.CallExp { id = $1; args = $3 } }

| IF exp THEN exp { Syntax.IfExp { test = $2; then' = $4; else' = None } }

diff --git a/test/tiger_test.expected b/test/tiger_test.expected

index f44e0a3..46a52c8 100644

--- a/test/tiger_test.expected

+++ b/test/tiger_test.expected

@@ -30,3 +30,4 @@ result: 4649

Hello World!!

Goodbye World!!

result: 55

+result: -30

diff --git a/test/tiger_test.ml b/test/tiger_test.ml

index 2a32255..a09b543 100644

--- a/test/tiger_test.ml

+++ b/test/tiger_test.ml

@@ -301,3 +301,15 @@ let () =

in print_string "result: ";

Tiger.Eval.print_val (eval src);

print_newline ()

+

+(* 負の整数リテラル *)

+let () =

+ let src = {|

+ let var a := -10

+ in -10 + -a

+ end

+ |}

+ in

+ print_string "result: ";

+ Tiger.Eval.print_val (eval src);

+ print_newline ()