Allow printing a prettytable to anything that implements Write

For example, stderr instead of stdout.

Depends on phsym/prettytable-rs#156

Cargo.toml

@@ -14,6 +14,7 @@ license = "MIT"
 readme = "README.md"
 repository = "https://github.com/romankoblov/prettydiff"
 homepage = "https://github.com/romankoblov/prettydiff"
+rust-version = "1.70"
 
 [dependencies]
 ansi_term.version = "0.12"
@@ -27,3 +28,6 @@ structopt.optional = true
 [features]
 cli = ["prettytable-rs", "structopt"]
 default = ["cli"]
+
+[patch.crates-io]
+prettytable-rs = { git = "https://github.com/asomers/prettytable-rs.git", rev = "1e2c2d5c3" }

src/text.rs

@@ -338,8 +338,7 @@ impl<'a> LineChangeset<'a> {
     }
 
     #[cfg(feature = "prettytable-rs")]
-    /// Prints side-by-side diff in table
-    pub fn prettytable(&self) {
+    fn prettytable_mktable(&self) -> prettytable::Table {
         let mut table = format_table::new();
         if let Some((old, new)) = &self.names {
             let mut header = vec![];
@@ -395,9 +394,25 @@ impl<'a> LineChangeset<'a> {
                 table.add_row(row![old, new]);
             }
         }
+        table
+    }
+
+    #[cfg(feature = "prettytable-rs")]
+    /// Prints side-by-side diff in table
+    pub fn prettytable(&self) {
+        let table = self.prettytable_mktable();
         table.printstd();
     }
 
+    #[cfg(feature = "prettytable-rs")]
+    /// Write side-by-side diff in table to any Writer.
+    pub fn write_prettytable<W>(&self, f: &mut W) -> std::io::Result<usize>
+        where W: std::io::Write + std::io::IsTerminal
+    {
+        let table = self.prettytable_mktable();
+        table.print_term(f)
+    }
+
     fn remove_color(&self, a: &str) -> String {
         Colour::Red.strikethrough().paint(a).to_string()
     }