From f76be43d265862414fb6ca11383c5891d1026d17 Mon Sep 17 00:00:00 2001
From: Antonio Yang <antonio.yang@siliconmotion.com.tw>
Date: Sun, 9 Jun 2019 11:12:31 +0800
Subject: [PATCH] str.isprintable

- check unicode type by unicode_categories
- rm redundant check of empty string
---
 tests/snippets/strings.py |  7 +++++++
 vm/Cargo.toml             |  1 +
 vm/src/obj/objstr.rs      | 26 ++++++++++++++++++++++++++
 3 files changed, 34 insertions(+)

diff --git a/tests/snippets/strings.py b/tests/snippets/strings.py
index aaeaed5f3e6..19cd98269a1 100644
--- a/tests/snippets/strings.py
+++ b/tests/snippets/strings.py
@@ -216,3 +216,10 @@ def try_mutate_str():
 for s, b, e in zip(ss, bs, ['u8', 'U8', 'utf-8', 'UTF-8', 'utf_8']):
     assert s.encode(e) == b
     # assert s.encode(encoding=e) == b
+
+# str.isisprintable
+assert "".isprintable()
+assert " ".isprintable()
+assert "abcdefg".isprintable()
+assert not "abcdefg\n".isprintable()
+assert "ʹ".isprintable()
diff --git a/vm/Cargo.toml b/vm/Cargo.toml
index ddc8ee20c02..cc7fe23b6c5 100644
--- a/vm/Cargo.toml
+++ b/vm/Cargo.toml
@@ -31,6 +31,7 @@ hexf = "0.1.0"
 indexmap = "1.0.2"
 crc = "^1.0.0"
 bincode = "1.1.4"
+unicode_categories = "0.1.1"
 
 
 # TODO: release and publish to crates.io
diff --git a/vm/src/obj/objstr.rs b/vm/src/obj/objstr.rs
index 40d19129685..8ea5cd6993f 100644
--- a/vm/src/obj/objstr.rs
+++ b/vm/src/obj/objstr.rs
@@ -1,3 +1,4 @@
+extern crate unicode_categories;
 extern crate unicode_xid;
 
 use std::fmt;
@@ -27,6 +28,8 @@ use super::objsequence::PySliceableSequence;
 use super::objslice::PySlice;
 use super::objtype::{self, PyClassRef};
 
+use unicode_categories::UnicodeCategories;
+
 /// str(object='') -> str
 /// str(bytes_or_buffer[, encoding[, errors]]) -> str
 ///
@@ -519,6 +522,29 @@ impl PyString {
         }
     }
 
+    /// Return true if all characters in the string are printable or the string is empty,
+    /// false otherwise.  Nonprintable characters are those characters defined in the
+    /// Unicode character database as `Other` or `Separator`,
+    /// excepting the ASCII space (0x20) which is considered printable.
+    ///
+    /// All characters except those characters defined in the Unicode character
+    /// database as following categories are considered printable.
+    ///   * Cc (Other, Control)
+    ///   * Cf (Other, Format)
+    ///   * Cs (Other, Surrogate)
+    ///   * Co (Other, Private Use)
+    ///   * Cn (Other, Not Assigned)
+    ///   * Zl Separator, Line ('\u2028', LINE SEPARATOR)
+    ///   * Zp Separator, Paragraph ('\u2029', PARAGRAPH SEPARATOR)
+    ///   * Zs (Separator, Space) other than ASCII space('\x20').
+    #[pymethod]
+    fn isprintable(&self, _vm: &VirtualMachine) -> bool {
+        self.value.chars().all(|c| match c {
+            '\u{0020}' => true,
+            _ => !(c.is_other_control() | c.is_separator()),
+        })
+    }
+
     // cpython's isspace ignores whitespace, including \t and \n, etc, unless the whole string is empty
     // which is why isspace is using is_ascii_whitespace. Same for isupper & islower
     #[pymethod]