7 Debugging tools
| (require (planet untyped/unlib/debug)) |
Utilities for printing the runtime values of variables for debugging purposes, with minimal disruption to code structure.
| (debug-enabled?) → boolean? |
| (debug-enabled? val) → void? |
| val : boolean? |
Boolean parameter for enabling or disabling the printing of debugging information. Defaults to #t.
| (current-debug-printer) → (-> string? any void?) |
| (current-debug-printer proc) → void? |
| proc : (-> string? any void?) |
Parameter controlling the formatting of printed debugging information. Value must be a procedure that takes a message and a value and returns void. The default value prints the message and a colon on one line and pretty-prints the value (slightly indented) on subsequent lines.
| (debug val) → any |
| val : any |
Prints val and returns it transparently.
Example: |
| > (length (debug "square" | | (for/list ([j '(1 2 3 4 5)]) | | (for/list ([i '(1 2 3 4 5)]) | | i)))) |
|
square: | ((1 2 3 4 5) | (1 2 3 4 5) | (1 2 3 4 5) | (1 2 3 4 5) | (1 2 3 4 5)) |
|
5 |
| (debug* proc arg ...) → any |
| proc : procedure? |
| arg : any |
Applies proc to args and prints and returns the return value transparently.
Example: |
| > (add1 (debug* "message" * 2 2)) |
|
5 |
Expands to a define form that prints the value of id as a side effect.
Example: |
| > (define/debug test-data | | (+ 1 2 3)) |
|
|
| (define-values/debug (id ...) expr) |
Like define/debug but expands to a define-values form.
Example: |
| > (define-values/debug (a b) | | (values (+ 1 2) (+ 3 4))) |
|
|
| (let/debug ([id expr] ...) expr ...) |
| (let/debug loop-id ([id expr] ...) expr ...) |
Expands to a let form that prints the value of each id as it is assigned. In "let loop" form, values are printed at the start of each call to loop-id.
Example: |
| > (let/debug ([a 1] [b 2]) | | (+ a b)) |
|
|
3 |
| (let*/debug ([id expr] ...) expr ...) |
Like let/debug but expands to a let* form.
| (letrec/debug ([id expr] ...) expr ...) |
Like let/debug but expands to a letrec form.
| (let-values/debug ([(id ...) expr] ...) expr ...) |
Expands to a let-values form that prints the value of each id as it is assigned.
Example: |
| > (let-values/debug ([(a b) (values 1 2)] [(c d) (values 3 4)]) | | (+ a b c d)) |
|
(a b): | (1 2) | (c d): | (3 4) |
|
10 |
| (let*-values/debug ([(id ...) expr] ...) expr ...) |
Like let-values/debug but expands to a let*-values form.
| (letrec-values/debug ([(id ...) expr] ...) expr ...) |
Like letrec-values/debug but expands to a letrec-values form.
| (with-pretty-indent prefix expr ...) |
Parameterizes the pretty-print-print-line parameter to a procedure that acts the same as the default, except that every line is prefixed with prefix. prefix must be a string.
Examples: |
| > (define square | | (for/list ([j '(1 2 3 4 5)]) | | (for/list ([i '(1 2 3 4 5)]) | | i))) |
|
| > (pretty-print square) |
((1 2 3 4 5) | (1 2 3 4 5) | (1 2 3 4 5) | (1 2 3 4 5) | (1 2 3 4 5)) |
|
| > (with-pretty-indent "..." | | (pretty-print square)) |
|
...((1 2 3 4 5) | ... (1 2 3 4 5) | ... (1 2 3 4 5) | ... (1 2 3 4 5) | ... (1 2 3 4 5)) |
|
| (exn-context exn) → (listof symbol?) |
| exn : exn? |
Returns a printable form of the continuation marks of exn that can can be used with pretty-print to produce simple, legible debugging output.
| (debug-in string require-spec) |
require form that behaves like require-spec but prints the imported identifiers using debug.
| (debug-out string require-spec) |
provide form that behaves like provide-spec but prints the exported identifiers using debug.