Add unary operators and parentheses

src/ast.cpp

@@ -85,6 +85,26 @@ void Binop::print_ast(std::ostream &out, unsigned int depth) const
   right->print_ast(out, depth+1);
 }
 
+void Unop::print_ast(std::ostream &out, unsigned int depth) const
+{
+  std::string indent(depth, ' ');
+  std::string opstr;
+  switch (op) {
+    case ebpf::bpftrace::Parser::token::LNOT:
+      opstr = "!";
+      break;
+    case ebpf::bpftrace::Parser::token::BNOT:
+      opstr = "~";
+      break;
+    default:
+      opstr = "???";
+      break;
+  }
+
+  out << indent << opstr << std::endl;
+  expr->print_ast(out, depth+1);
+}
+
 void ExprStatement::print_ast(std::ostream &out, unsigned int depth) const
 {
   std::string indent(depth, ' ');

src/ast.h

@@ -42,6 +42,14 @@ public:
   int op;
 };
 
+class Unop : public Expression {
+public:
+  Unop(int op, Expression *expr) : expr(expr), op(op) { }
+  void print_ast(std::ostream &out, unsigned int depth = 0) const override;
+  Expression *expr;
+  int op;
+};
+
 class Statement : public Node {
 };
 using StatementList = std::vector<Statement *>;

src/lexer.l

@@ -34,6 +34,8 @@ using namespace ebpf::bpftrace;
 "}"                     { return Parser::make_RBRACE(loc); }
 "["                     { return Parser::make_LBRACKET(loc); }
 "]"                     { return Parser::make_RBRACKET(loc); }
+"("                     { return Parser::make_LPAREN(loc); }
+")"                     { return Parser::make_RPAREN(loc); }
 \//[ \t\n\r]*[\/\{]     { return Parser::make_ENDPRED(loc); } // If "/" is followed by "/" or "{", choose ENDPRED, otherwise DIV
 ","                     { return Parser::make_COMMA(loc); }
 "="                     { return Parser::make_ASSIGN(loc); }

src/parser.yy

@@ -43,6 +43,8 @@ void yyerror(ebpf::bpftrace::Driver &driver, const char *s);
   RBRACE   "}"
   LBRACKET "["
   RBRACKET "]"
+  LPAREN   "("
+  RPAREN   ")"
   ENDPRED  "end predicate"
   COMMA    ","
   ASSIGN   "="
@@ -119,6 +121,7 @@ stmt : expr         { $$ = new ast::ExprStatement($1); }
 
 expr : INT             { $$ = new ast::Integer($1); }
      | var             { $$ = $1; }
+     | "(" expr ")"    { $$ = $2; }
      | expr EQ expr    { $$ = new ast::Binop($1, token::EQ, $3); }
      | expr NE expr    { $$ = new ast::Binop($1, token::NE, $3); }
      | expr LE expr    { $$ = new ast::Binop($1, token::LE, $3); }
@@ -135,6 +138,8 @@ expr : INT             { $$ = new ast::Integer($1); }
      | expr BAND expr  { $$ = new ast::Binop($1, token::BAND,  $3); }
      | expr BOR expr   { $$ = new ast::Binop($1, token::BOR,   $3); }
      | expr BXOR expr  { $$ = new ast::Binop($1, token::BXOR,  $3); }
+     | LNOT expr       { $$ = new ast::Unop(token::LNOT, $2); }
+     | BNOT expr       { $$ = new ast::Unop(token::BNOT, $2); }
      ;
 
 var : IDENT               { $$ = new ast::Variable($1); }