Move ExecProgram to interpreter/ (#802)

Seems to make sense since it's the only interpreter/ dependency in syntax/ right now, so this feels like untangling deps.

Fixes #371

executable_semantics/syntax/BUILD

@@ -2,10 +2,10 @@
 # Exceptions. See /LICENSE for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-package(default_visibility = ["//executable_semantics:__pkg__"])
-
 load("@mypy_integration//:mypy.bzl", "mypy_test")
 
+package(default_visibility = ["//executable_semantics:__pkg__"])
+
 cc_library(
     name = "bison_wrap",
     hdrs = ["bison_wrap.h"],
@@ -22,8 +22,6 @@ cc_library(
         "parse_and_lex_context.h",
         "parser.cpp",
         "parser.h",
-        "syntax_helpers.cpp",
-        "syntax_helpers.h",
     ],
     hdrs = [
         "parse.h",
@@ -45,8 +43,6 @@ cc_library(
         "//executable_semantics/common:arena",
         "//executable_semantics/common:error",
         "//executable_semantics/common:tracing_flag",
-        "//executable_semantics/interpreter",
-        "//executable_semantics/interpreter:type_checker",
     ],
 )
 

executable_semantics/syntax/parser.ypp

@@ -59,7 +59,6 @@
 
   #include "common/check.h"
   #include "executable_semantics/syntax/parse_and_lex_context.h"
-  #include "executable_semantics/syntax/syntax_helpers.h"
   #include "llvm/ADT/StringExtras.h"
 }  // %code top
 

executable_semantics/syntax/syntax_helpers.cpp

@@ -1,69 +0,0 @@
-// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-// Exceptions. See /LICENSE for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-#include "executable_semantics/syntax/syntax_helpers.h"
-
-#include "common/check.h"
-#include "common/ostream.h"
-#include "executable_semantics/common/arena.h"
-#include "executable_semantics/common/tracing_flag.h"
-#include "executable_semantics/interpreter/interpreter.h"
-#include "executable_semantics/interpreter/type_checker.h"
-
-namespace Carbon {
-
-// Adds builtins, currently only Print(). Note Print() is experimental, not
-// standardized, but is made available for printing state in tests.
-static void AddIntrinsics(std::list<Ptr<const Declaration>>* fs) {
-  SourceLocation loc("<intrinsic>", 0);
-  std::vector<TuplePattern::Field> print_fields = {TuplePattern::Field(
-      "0", global_arena->New<BindingPattern>(
-               loc, "format_str",
-               global_arena->New<ExpressionPattern>(
-                   global_arena->New<StringTypeLiteral>(loc))))};
-  auto print_return =
-      global_arena->New<Return>(loc,
-                                global_arena->New<IntrinsicExpression>(
-                                    IntrinsicExpression::IntrinsicKind::Print),
-                                false);
-  auto print = global_arena->New<FunctionDeclaration>(
-      global_arena->New<FunctionDefinition>(
-          loc, "Print", std::vector<GenericBinding>(),
-          global_arena->New<TuplePattern>(loc, print_fields),
-          global_arena->New<ExpressionPattern>(
-              global_arena->New<TupleLiteral>(loc)),
-          /*is_omitted_return_type=*/false, print_return));
-  fs->insert(fs->begin(), print);
-}
-
-void ExecProgram(std::list<Ptr<const Declaration>> fs) {
-  AddIntrinsics(&fs);
-  if (tracing_output) {
-    llvm::outs() << "********** source program **********\n";
-    for (const auto decl : fs) {
-      llvm::outs() << *decl;
-    }
-    llvm::outs() << "********** type checking **********\n";
-  }
-  TypeChecker type_checker;
-  TypeChecker::TypeCheckContext p = type_checker.TopLevel(fs);
-  TypeEnv top = p.types;
-  Env ct_top = p.values;
-  std::list<Ptr<const Declaration>> new_decls;
-  for (const auto decl : fs) {
-    new_decls.push_back(type_checker.MakeTypeChecked(decl, top, ct_top));
-  }
-  if (tracing_output) {
-    llvm::outs() << "\n";
-    llvm::outs() << "********** type checking complete **********\n";
-    for (const auto decl : new_decls) {
-      llvm::outs() << *decl;
-    }
-    llvm::outs() << "********** starting execution **********\n";
-  }
-  int result = Interpreter().InterpProgram(new_decls);
-  llvm::outs() << "result: " << result << "\n";
-}
-
-}  // namespace Carbon

executable_semantics/syntax/syntax_helpers.h

@@ -1,24 +0,0 @@
-// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-// Exceptions. See /LICENSE for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-// Helpers should be added here when logic in syntax.ypp is more than a single
-// statement. The intent is to minimize the amount of C++ in the .ypp file, to
-// improve ease of maintenance.
-
-#ifndef EXECUTABLE_SEMANTICS_EXEC_H_
-#define EXECUTABLE_SEMANTICS_EXEC_H_
-
-#include <list>
-
-#include "executable_semantics/ast/declaration.h"
-#include "executable_semantics/common/ptr.h"
-
-namespace Carbon {
-
-// Runs the top-level declaration list.
-void ExecProgram(std::list<Ptr<const Declaration>> fs);
-
-}  // namespace Carbon
-
-#endif  // EXECUTABLE_SEMANTICS_EXEC_H_