Add print_ast()

src/ast.cpp

+#include "ast.h"
+
+namespace ebpf {
+namespace bpftrace {
+namespace ast {
+
+void Integer::print_ast(std::ostream &out, unsigned int depth) const
+{
+  out << "int: " << n << std::endl;
+}
+
+void Identifier::print_ast(std::ostream &out, unsigned int depth) const
+{
+  out << "ident: " << ident << std::endl;
+}
+
+void Statement::print_ast(std::ostream &out, unsigned int depth) const
+{
+  out << "stmt" << std::endl;
+  out << std::string(depth, ' ');
+  expr->print_ast(out, depth+1);
+}
+
+void Probe::print_ast(std::ostream &out, unsigned int depth) const
+{
+  out << "Probe" << std::endl;
+  for (Statement *stmt : *stmts) {
+    out << std::string(depth, ' ');
+    stmt->print_ast(out, depth+1);
+  }
+}
+
+void Program::print_ast(std::ostream &out, unsigned int depth) const
+{
+  out << "Program" << std::endl;
+  ++depth;
+  for (Probe *probe : *probes) {
+    out << std::string(depth, ' ');
+    probe->print_ast(out, depth+1);
+  }
+}
+
+} // namespace ast
+} // namespace bpftrace
+} // namespace ebpf

src/ast.h

@@ -2,6 +2,7 @@
 
 #include <string>
 #include <vector>
+#include <ostream>
 
 namespace ebpf {
 namespace bpftrace {
@@ -10,6 +11,7 @@ namespace ast {
 class Node {
 public:
   virtual ~Node() { }
+  virtual void print_ast(std::ostream &out, unsigned int depth = 0) const = 0;
 };
 
 class Expression : public Node {
@@ -18,34 +20,30 @@ class Expression : public Node {
 class Integer : public Expression {
 public:
   explicit Integer(int n) : n(n) { }
+  void print_ast(std::ostream &out, unsigned int depth = 0) const override;
   int n;
 };
 
 class Identifier : public Expression {
 public:
   explicit Identifier(std::string &ident) : ident(ident) { }
+  void print_ast(std::ostream &out, unsigned int depth = 0) const override;
   std::string ident;
 };
 
 class Statement : public Node {
 public:
   explicit Statement(Expression *expr) : expr(expr) { }
+  void print_ast(std::ostream &out, unsigned int depth = 0) const override;
   Expression *expr;
 };
 using StatementList = std::vector<Statement *>;
 
-class PreProcessor : public Node {
-public:
-  explicit PreProcessor(const std::string &line) : line(line) { }
-
-  std::string line;
-};
-using PreProcessorList = std::vector<PreProcessor *>;
-
 class Probe : public Node {
 public:
   Probe(std::string type, std::string attach_point, StatementList *stmts)
     : type(type), attach_point(attach_point), stmts(stmts) { }
+  void print_ast(std::ostream &out, unsigned int depth = 0) const override;
 
   std::string type;
   std::string attach_point;
@@ -55,9 +53,8 @@ using ProbeList = std::vector<Probe *>;
 
 class Program : public Node {
 public:
-  Program(PreProcessorList *preprocs, ProbeList *probes)
-    : preprocs(preprocs), probes(probes) { }
-  PreProcessorList *preprocs;
+  explicit Program(ProbeList *probes) : probes(probes) { }
+  void print_ast(std::ostream &out, unsigned int depth = 0) const override;
   ProbeList *probes;
 };
 

src/lexer.l

@@ -25,7 +25,6 @@ using namespace ebpf::bpftrace;
 [\n\r]+                 { loc.lines(yyleng); loc.step(); }
 "//".*$  // Comments
 
-^"#".*$                 { return Parser::make_PREPROCESSOR(yytext, loc); }
 [_a-zA-Z][_a-zA-Z0-9]*  { return Parser::make_IDENT(yytext, loc); }
 [0-9]+                  { return Parser::make_INT(strtoul(yytext, NULL, 0), loc); }
 0[xX][0-9a-fA-F]+       { return Parser::make_INT(strtoul(yytext, NULL, 0), loc); }

src/main.cpp

@@ -12,8 +12,6 @@ int main(int argc, char *argv[])
     result = driver.parse(argv[1]);
   }
 
-  for (auto &preproc : *(driver.root_->preprocs)) {
-    std::cout << preproc->line << std::endl;
-  }
+  driver.root_->print_ast(std::cout);
   return result;
 }

src/parser.yy

@@ -44,11 +44,9 @@ void yyerror(ebpf::bpftrace::Driver &driver, const char *s);
   RBRACE  "}"
 ;
 
-%token <std::string> PREPROCESSOR "preprocessor"
 %token <std::string> IDENT "identifier"
 %token <int> INT "integer"
 
-%type <ast::PreProcessorList *> preprocs
 %type <ast::ProbeList *> probes
 %type <ast::StatementList *> block stmts
 %type <ast::Probe *> probe
@@ -61,17 +59,11 @@ void yyerror(ebpf::bpftrace::Driver &driver, const char *s);
 
 %%
 
-program : preprocs probes { driver.root_ = new ast::Program($1, $2); }
-        | probes
+program : probes { driver.root_ = new ast::Program($1); }
         ;
 
-preprocs : preprocs PREPROCESSOR { $$ = $1; $1->push_back(new ast::PreProcessor($2)); }
-         | PREPROCESSOR          { $$ = new ast::PreProcessorList;
-                                   $$->push_back(new ast::PreProcessor($1)); }
-
 probes : probes probe { $$ = $1; $1->push_back($2); }
-       | probe        { $$ = new ast::ProbeList;
-                        $$->push_back($1); }
+       | probe        { $$ = new ast::ProbeList; $$->push_back($1); }
        ;
 
 probe : IDENT ":" IDENT block { $$ = new ast::Probe($1, $3, $4); }