Stepping (SLIME User Manual, version 2.28)

### 4.4 Stepping

Stepping is not available in all implementations and works very differently in those in which it is available.

`s` ¶
`M-x sldb-step`

  Step to the next expression in the frame. For CMUCL that means, set a breakpoint at all those code locations in the current code block which are reachable from the current code location.

`x` ¶
`M-x sldb-next`

  Step to the next form in the current function.

`o` ¶
`M-x sldb-out`

  Stop single-stepping temporarily, but resume it once the current function returns.