Intermezzo 1: Syntax and Semantics [Beginning Student]

The Scheme Vocabulary - no notes

No DrScheme notes for this section.

The Scheme Grammar

DrScheme provides special Scheme-specific editing commands for manipulating expressions:

Command Key Binding
Move forward past an expression ESC-right or ESC-Ctl-F
Move backward past an expression ESC-left or ESC-Ctl-B
Select forward expression ESC-shift-right or ESC-Ctl-Shift-F
Select backward expression ESC-shift-left or ESC-Ctl-Shift-B
Move outside an expression ESC-up or ESC-Ctl-U
Move inside an expression ESC-down or ESC-Ctl-D

``ESC-right'' means ``push the ESC key, let go, and then push the right arrow key.''

The Meaning of Scheme

See Stepping for information about using DrScheme's Stepper to step through expressions mechanically.

To write down step-by-step evaluations ``by hand,'' DrScheme's definitions window can be used as a plain text editor. The cut and paste functions, available from the menu or through the usual key bindings, make it easy to copy the expression from one step as a starting point for the next step. The keybindings described in the previous section are also useful.

Errors - no notes

No DrScheme notes for this section.

Boolean Expressions - no notes

No DrScheme notes for this section.

Variable Definitions - no notes

No DrScheme notes for this section.

Structure Definitions - no notes

No DrScheme notes for this section.