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# Using DrScheme

How do I find general help for DrScheme?

Select Help Desk in DrScheme's Help menu.

How do I run MrSpidey, DrScheme's program analyzer?

MrSpidey is distributed separately from the standard DrScheme distribution. Download MrSpidey from

`http://www.cs.rice.edu/CS/PLT/packages/mrspidey/`

What happened to the Analyze button?

Starting with version 51, PLT distributes DrScheme without the MrSpidey analysis tool. See the previous answer for information about obtaining MrSpidey.

How do I customize DrScheme?

The Edit menu contains a Preferences item that opens the preferences dialog.

How do I turn off parenthesis-flashing and the gray background behind expressions?

Use the Edit|Preferences menu item.

What are the key bindings in DrScheme?

Some basic key bindings are listed in the DrScheme manual, which is accessible via the Help button in DrScheme.

Can I change the key bindings in DrScheme?

Technically, yes, but that requires in-depth information about the way that DrScheme is implemented. (The necessary information is part of the MrEd toolbox manual.) DrScheme currently provides no simple way to adjust the keyboard mappings, other than to set the behavior of the Delete key (via the preferences dialog).

What do those yellow-and-black messages mean, and how do I get rid of them?

When text in the definitions window is modified, the current language is changed, or the current library is changed, DrScheme pessimistically assumes that some definition has been changed. In this case, expressions evaluated in the interaction window would use definitions that do not match those currently displayed in the definitions windows. A yellow-and-black message warns you about this potential inconsistency, and suggests that you resolve the inconsistency by clicking the Execute button. To suppress all but the first warning, see the General II panel in the Preferences dialog.

Why can't I type in the interaction window before the the current prompt?

To prevent accidental revisions of the interaction history, DrScheme disallows editing before the current prompt. While old expressions cannot be edited in place, you can copy old expressions to the current prompt by typing Esc-p. Alternatively, place the insertion caret at the end of any old expression in the interactions window and type Enter or Return to copy the expression down to the current prompt.

Is there a DrScheme compiler?

DrScheme is a compiler; each time the user loads a program or enters expression in the interactions window, DrScheme compiles and then executes the program or expression.

PLT's `mzc` transforms Scheme programs into C programs, and then uses a third-party C compiler to produce executable code. Under Windows, either Microsoft Visual C or gcc (a free compiler from Cygnus Solutions) works as the C compiler. Under MacOS, CodeWarrior works. Under Unix, most any compiler works.

For details, see the `mzc` documentation, available from:

`http://www.cs.rice.edu/CS/PLT/packages/doc/`

Can I produce stand-alone executables from Scheme code?

The `mzc` compiler can be used to produce stand-alone executables, but only with significant effort. See the `mzc` documentation for more information.

Can files saved in DrScheme be transferred between platforms?

DrScheme saves files in two formats: text and multimedia.

The text format is the usual platform-specific text format. Tools for moving files between platforms typically support a ``text'' transfer mode that adjusts newlines and carriage returns in the test as appropriate.

The multimedia format, used for saving files that contain pictures or formatted text, is platform-indepdendent. Although no other program is able to read DrScheme's special format, a multimedia-format file can be moved between different platforms (in ``binary'' mode) and DrScheme will read it correctly on the destination platform.

Next: Memory and Performance Up: Frequently Asked Questions Previous: Supported Operating Systems and