console: only color outputs if stdout isa TTY

[nit.git] / lib / console.nit

diff --git a/lib/console.nit b/lib/console.nit
index 3333cad..1a68ff3 100644 (file)
--- a/lib/console.nit
+++ b/lib/console.nit
@@ -13,6 +13,10 @@
 # limitations under the License.
 
 # Defines some ANSI Terminal Control Escape Sequences.
+#
+# The color methods (e.g. `Text::green`) format the text to appear colored
+# in a ANSI/VT100 terminal. By default, this coloring is skipped if stdout
+# is not a TTY, but it can be forced by setting `force_console_colors = true`.
 module console
 
 # A ANSI/VT100 escape sequence.
@@ -279,10 +283,12 @@ class TermCharFormat
        fun default_bg: TermCharFormat do return apply("49")
 end
 
-# Redefine the `String` class to add functions to color the string.
-redef class String
+# Services to color terminal output
+redef class Text
        private fun apply_format(f: TermCharFormat): String do
-               return "{f}{self}{normal}"
+               if stdout_isatty or force_console_colors then
+                       return "{f}{self}{normal}"
+               else return to_s
        end
 
        private fun normal: TermCharFormat do return new TermCharFormat
@@ -409,3 +415,12 @@ class TermProgress
                display(metadata)
        end
 end
+
+redef class Sys
+       private var stdout_isatty: Bool = 1.isatty is lazy
+
+       # Force coloring terminal output, even if stdout is not a TTY?
+       #
+       # Defaults to `false`.
+       var force_console_colors = false is writable
+end