prompt format string for literal backslash

In case the user wanted to write a literal "\h" for some reason, that
was previously not possible.

This still doesn't work right for "\x", since that is interpreted
later, something we can address by unifying.

Author: rolandwalker

changelog.md

@@ -1,3 +1,11 @@
+Upcoming (TBD)
+==============
+
+Features
+---------
+* Add prompt format string for literal backslash.
+
+
 1.64.0 (2026/03/13)
 ==============
 

mycli/main.py

@@ -1702,6 +1702,8 @@ def get_prompt(self, string: str, _render_counter: int) -> str:
         if re.match(r'^[\d\.]+$', short_prompt_host):
             short_prompt_host = prompt_host
         now = datetime.now()
+        backslash_placeholder = '\ufffc_backslash'
+        string = string.replace('\\\\', backslash_placeholder)
         string = string.replace("\\u", sqlexecute.user or "(none)")
         string = string.replace("\\h", prompt_host or "(none)")
         string = string.replace("\\H", short_prompt_host or "(none)")
@@ -1721,6 +1723,7 @@ def get_prompt(self, string: str, _render_counter: int) -> str:
         string = string.replace("\\K", sqlexecute.socket or str(sqlexecute.port))
         string = string.replace("\\A", self.dsn_alias or "(none)")
         string = string.replace("\\_", " ")
+        string = string.replace(backslash_placeholder, '\\')
 
         # jump through hoops for the test environment, and for efficiency
         if hasattr(sqlexecute, 'conn') and sqlexecute.conn is not None:

mycli/myclirc

@@ -124,6 +124,7 @@ wider_completion_menu = False
 # * \A - DSN alias
 # * \n - a newline
 # * \_ - a space
+# * \\ - a literal backslash
 # * \x1b[...m - an ANSI escape sequence (can style with color)
 prompt = '\t \u@\h:\d> '
 prompt_continuation = '->'

test/myclirc

@@ -122,6 +122,7 @@ wider_completion_menu = False
 # * \A - DSN alias
 # * \n - a newline
 # * \_ - a space
+# * \\ - a literal backslash
 # * \x1b[...m - an ANSI escape sequence (can style with color)
 prompt = "\t \u@\h:\d> "
 prompt_continuation = ->