diff --git a/code/compiler/13/parser.y b/code/compiler/13/parser.y
index 44c4215..528f75f 100644
--- a/code/compiler/13/parser.y
+++ b/code/compiler/13/parser.y
@@ -18,6 +18,7 @@ using yyscan_t = void*;
 }
 
 %token BACKSLASH
+%token BACKTICK
 %token PLUS
 %token TIMES
 %token MINUS
@@ -52,9 +53,10 @@ using yyscan_t = void*;
 %type <std::vector<branch_ptr>> branches
 %type <std::vector<constructor_ptr>> constructors
 %type <std::vector<parsed_type_ptr>> typeList
+%type <binop> anyBinop
 %type <definition_group> definitions
 %type <parsed_type_ptr> type nonArrowType typeListElement
-%type <ast_ptr> aEq aAdd aMul case let lambda app appBase
+%type <ast_ptr> aInfix aEq aAdd aMul case let lambda app appBase
 %type <definition_data_ptr> data 
 %type <definition_defn_ptr> defn
 %type <branch_ptr> branch
@@ -76,7 +78,7 @@ definitions
     ;
 
 defn
-    : DEFN LID lowercaseParams EQUAL OCURLY aEq CCURLY
+    : DEFN LID lowercaseParams EQUAL OCURLY aInfix CCURLY
         { $$ = definition_defn_ptr(
             new definition_defn(std::move($2), std::move($3), std::move($6), @$)); }
     ;
@@ -86,6 +88,16 @@ lowercaseParams
     | lowercaseParams LID { $$ = std::move($1); $$.push_back(std::move($2)); }
     ;
 
+aInfix
+    : aInfix BACKTICK LID BACKTICK aEq
+        { $$ = ast_ptr(new ast_app(
+            ast_ptr(new ast_app(ast_ptr(new ast_lid(std::move($3))), std::move($1))), std::move($5))); }
+    | aInfix BACKTICK UID BACKTICK aEq
+        { $$ = ast_ptr(new ast_app(
+            ast_ptr(new ast_app(ast_ptr(new ast_uid(std::move($3))), std::move($1))), std::move($5))); }
+    | aEq { $$ = std::move($1); }
+    ;
+
 aEq
     : aAdd EQUALS aAdd { $$ = ast_ptr(new ast_binop(EQUALS, std::move($1), std::move($3), @$)); }
     | aAdd LESS_EQUALS aAdd { $$ = ast_ptr(new ast_binop(LESS_EQUALS, std::move($1), std::move($3), @$)); }
@@ -114,24 +126,35 @@ appBase
     : INT { $$ = ast_ptr(new ast_int($1, @$)); }
     | LID { $$ = ast_ptr(new ast_lid(std::move($1), @$)); }
     | UID { $$ = ast_ptr(new ast_uid(std::move($1), @$)); }
-    | OPAREN aEq CPAREN { $$ = std::move($2); }
+    | OPAREN aInfix CPAREN { $$ = std::move($2); }
+    | OPAREN anyBinop CPAREN { $$ = ast_ptr(new ast_lid(op_name($2))); }
     | case { $$ = std::move($1); }
     | let { $$ = std::move($1); }
     | lambda { $$ = std::move($1); }
     ;
 
+anyBinop
+    : PLUS { $$ = PLUS; }
+    | MINUS { $$ = MINUS; }
+    | TIMES { $$ = TIMES; }
+    | DIVIDE { $$ = DIVIDE; }
+    | MODULO { $$ = MODULO; }
+    | EQUALS { $$ = EQUALS; }
+    | LESS_EQUALS { $$ = LESS_EQUALS; }
+    ;
+
 let
-    : LET OCURLY definitions CCURLY IN OCURLY aAdd CCURLY
+    : LET OCURLY definitions CCURLY IN OCURLY aInfix CCURLY
         { $$ = ast_ptr(new ast_let(std::move($3), std::move($7), @$)); }
     ;
 
 lambda
-    : BACKSLASH lowercaseParams ARROW OCURLY aAdd CCURLY
+    : BACKSLASH lowercaseParams ARROW OCURLY aInfix CCURLY
         { $$ = ast_ptr(new ast_lambda(std::move($2), std::move($5), @$)); }
     ;
 
 case
-    : CASE aAdd OF OCURLY branches CCURLY 
+    : CASE aInfix OF OCURLY branches CCURLY 
         { $$ = ast_ptr(new ast_case(std::move($2), std::move($5), @$)); }
     ;
 
@@ -141,7 +164,7 @@ branches
     ;
 
 branch
-    : pattern ARROW OCURLY aAdd CCURLY
+    : pattern ARROW OCURLY aInfix CCURLY
         { $$ = branch_ptr(new branch(std::move($1), std::move($4))); }
     ;
 
diff --git a/code/compiler/13/scanner.l b/code/compiler/13/scanner.l
index 162643d..ddd46da 100644
--- a/code/compiler/13/scanner.l
+++ b/code/compiler/13/scanner.l
@@ -29,6 +29,7 @@
 % { return yy::parser::make_MODULO(drv.location); }
 == { return yy::parser::make_EQUALS(drv.location); }
 \<= { return yy::parser::make_LESS_EQUALS(drv.location); }
+` { return yy::parser::make_BACKTICK(drv.location); }
 [0-9]+ { return yy::parser::make_INT(atoi(yytext), drv.location); }
 defn { return yy::parser::make_DEFN(drv.location); }
 data { return yy::parser::make_DATA(drv.location); }