Expand documentation for eval mode (#254)

* Expand documentation for eval mode

Includes how one exits eval mode. Fixes #253.

Author: timholy

README.md

@@ -39,6 +39,8 @@ the context of functions.
 
 Below, square brackets denote optional arguments.
 
+All of the following commands work when the prompt is `1|debug>`:
+
 Misc:
 - `o`: open the current line in an editor
 - `q`: quit the debugger, returning `nothing`
@@ -67,7 +69,6 @@ Querying:
 - `fr [i::Int]`: show all variables in the current or `i`th frame
 
 Evaluation:
-- ``` `stuff ```: run `stuff` in the current function's context
 - `w`
     - `w add expr`: add an expression to the watch list
     - `w`: show all watch expressions evaluated in the current function's context
@@ -92,6 +93,15 @@ Breakpoints:
 
 An empty command will execute the previous command.
 
+Changing frames with `f i::Int` will change the prompt to `$i|debug>`.
+Stepping commands will not work until you return to `f 1`, but a subset of normal commands will continue to work.
+
+In addition to these debugging commands, you can type `` ` `` to enter "evaluation mode" indicated by a prompt `$i|julia>`.
+In evaluation mode, any expression you type is executed in the debug context.
+For example, if you have a local variable named `n`, then once in evaluation mode typing `n` will show you the value of `n` rather than advancing to the next line.
+
+Hit backspace as the first character of the line to return to "debug mode."
+
 ### Breakpoints
 
 To add and manipulate breakpoints, either the `bp add` command in the debug interface or the JuliaInterpreter breakpoint API, documented [here](https://juliadebug.github.io/JuliaInterpreter.jl/latest/dev_reference/#Breakpoints-1)

src/commands.jl

@@ -270,7 +270,6 @@ function execute_command(state::DebuggerState, ::Union{Val{:help}, Val{:?}}, cmd
 
 
             Evaluation:\\
-            - ``` `stuff ```: run `stuff` in the current function's context\\
             - `w`\\
                 - `w add expr`: add an expression to the watch list\\
                 - `w`: show all watch expressions evaluated in the current function's context\\
@@ -294,7 +293,10 @@ function execute_command(state::DebuggerState, ::Union{Val{:help}, Val{:?}}, cmd
                 - `bp on/off throw` - turn on or off break on throw\\
 
 
-            An empty command will execute the previous command.""")
+            An empty command will execute the previous command.
+        
+            Hit `` ` `` to enter "evaluation mode," where any expression you type is executed in the debug context.
+            Hit backspace as the first character of the line (or `^C` anywhere) to return to "debug mode." """)
     return false
 end