Support raw string literals as input for py::eval (#766)
* Support raw string literals as input for py::eval
* Dedent only when needed
diff --git a/docs/advanced/pycpp/utilities.rst b/docs/advanced/pycpp/utilities.rst
index ba0dbef..442d0e9 100644
--- a/docs/advanced/pycpp/utilities.rst
+++ b/docs/advanced/pycpp/utilities.rst
@@ -55,3 +55,18 @@
// Evaluate the statements in an separate Python file on disk
py::eval_file("script.py", scope);
+
+C++11 raw string literals are also supported and quite handy for this purpose.
+The only requirement is that the first statement must be on a new line following
+the raw string delimiter ``R"(``, ensuring all lines have common leading indent:
+
+.. code-block:: cpp
+
+ py::eval<py::eval_statements>(R"(
+ x = get_answer()
+ if x == 42:
+ print('Hello World!')
+ else:
+ print('Bye!')
+ )", scope
+ );
diff --git a/include/pybind11/eval.h b/include/pybind11/eval.h
index 5b2b982..d4d26c1 100644
--- a/include/pybind11/eval.h
+++ b/include/pybind11/eval.h
@@ -11,8 +11,6 @@
#pragma once
-#pragma once
-
#include "pybind11.h"
NAMESPACE_BEGIN(pybind11)
@@ -56,6 +54,14 @@
return reinterpret_steal<object>(result);
}
+template <eval_mode mode = eval_expr, size_t N>
+object eval(const char (&s)[N], object global = object(), object local = object()) {
+ /* Support raw string literals by removing common leading whitespace */
+ auto expr = (s[0] == '\n') ? str(module::import("textwrap").attr("dedent")(s))
+ : str(s);
+ return eval<mode>(expr, global, local);
+}
+
template <eval_mode mode = eval_statements>
object eval_file(str fname, object global = object(), object local = object()) {
if (!global) {
diff --git a/tests/test_eval.cpp b/tests/test_eval.cpp
index ed4c226..05cc7f0 100644
--- a/tests/test_eval.cpp
+++ b/tests/test_eval.cpp
@@ -20,11 +20,21 @@
return 42;
});
- auto result = py::eval<py::eval_statements>(
- "print('Hello World!');\n"
- "x = call_test();",
+ // Regular string literal
+ py::eval<py::eval_statements>(
+ "message = 'Hello World!'\n"
+ "x = call_test()",
global, local
);
+
+ // Multi-line raw string literal
+ auto result = py::eval<py::eval_statements>(R"(
+ if x == 42:
+ print(message)
+ else:
+ raise RuntimeError
+ )", global, local
+ );
auto x = local["x"].cast<int>();
return result == py::none() && x == 42;