1 files changed, 29 insertions, 0 deletions
diff --git a/examples/prompts/custom-lexer.py b/examples/prompts/custom-lexer.py
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+++ b/examples/prompts/custom-lexer.py
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+#!/usr/bin/env python
+"""
+An example of a custom lexer that prints the input text in random colors.
+"""
+from prompt_toolkit.lexers import Lexer
+from prompt_toolkit.shortcuts import prompt
+from prompt_toolkit.styles.named_colors import NAMED_COLORS
+
+
+class RainbowLexer(Lexer):
+    def lex_document(self, document):
+        colors = list(sorted(NAMED_COLORS, key=NAMED_COLORS.get))
+
+        def get_line(lineno):
+            return [
+                (colors[i % len(colors)], c)
+                for i, c in enumerate(document.lines[lineno])
+            ]
+
+        return get_line
+
+
+def main():
+    answer = prompt("Give me some input: ", lexer=RainbowLexer())
+    print("You said: %s" % answer)
+
+
+if __name__ == "__main__":
+    main()