Thanks for the comments. Unfortunately, it doesn’t work. Here is the error:
1|julia > println($op)
ERROR: UndefVarError: op not defined
in _step_expr(::ASTInterpreter.Interpreter) at /home/chobbes/.julia/v0.5/ASTInterpreter/src/ASTInterpreter.jl:653
in step_expr at /home/chobbes/.julia/v0.5/ASTInterpreter/src/ASTInterpreter.jl:666 [inlined]
in #finish!#81(::Bool, ::Bool, ::Function, ::ASTInterpreter.Interpreter) at /home/chobbes/.julia/v0.5/ASTInterpreter/src/ASTInterpreter.jl:1720
in eval_in_interp(::ASTInterpreter.Interpreter, ::Expr, ::JuliaParser.Tokens.SourceExpr, ::String) at /home/chobbes/.julia/v0.5/ASTInterpreter/src/ASTInterpreter.jl:1298
in eval_code(::ASTInterpreter.InterpreterState, ::String) at /home/chobbes/.julia/v0.5/ASTInterpreter/src/ASTInterpreter.jl:1529
in (::ASTInterpreter.##72#78{ASTInterpreter.InterpreterState,Base.LineEdit.Prompt})(::Base.LineEdit.MIState, ::Base.AbstractIOBuffer{Array{UInt8,1}}, ::Bool) at /home/chobbes/.julia/v0.5/ASTInterpreter/src/ASTInterpreter.jl:1654
in run_interface(::Base.Terminals.TTYTerminal, ::Base.LineEdit.ModalInterface) at ./LineEdit.jl:1579
in RunDebugREPL(::ASTInterpreter.Interpreter) at /home/chobbes/.julia/v0.5/ASTInterpreter/src/ASTInterpreter.jl:1693
Apparently, interpolation doesn’t work this way in debugger.
I think if `println($op) works, `$op should have worked too.