Read

Read a byte

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (read-u8))

And a file named “input.txt” with:

When I run stak main.scm interactively

And I pipe in the file “input.txt”

Then the exit status should be 0

And the stdout should contain exactly “A”.

Read bytes

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (read-u8))
(write-u8 (read-u8))
(write-u8 (read-u8))

And a file named “input.txt” with:

ABC

When I run stak main.scm interactively

And I pipe in the file “input.txt”

Then the exit status should be 0

And the stdout should contain exactly “ABC”.

Peek a byte

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (peek-u8))

And a file named “input.txt” with:

When I run stak main.scm interactively

And I pipe in the file “input.txt”

Then the exit status should be 0

And the stdout should contain exactly “A”.

Peek a byte multiple times

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (peek-u8))
(write-u8 (peek-u8))

And a file named “input.txt” with:

When I run stak main.scm interactively

And I pipe in the file “input.txt”

Then the exit status should be 0

And the stdout should contain exactly “AA”.

Peek and read bytes

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (peek-u8))
(write-u8 (read-u8))
(write-u8 (read-u8))

And a file named “input.txt” with:

AB

When I run stak main.scm interactively

And I pipe in the file “input.txt”

Then the exit status should be 0

And the stdout should contain exactly “AAB”.

Check if a byte is ready or not.

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (u8-ready? (open-input-bytevector #u8(<bytes>))) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “<output>”.

Examples

bytes	output
	A
65	A

Read a character

Given a file named “main.scm” with:

(import (scheme base))

(write-char (read-char))

And a file named “input.txt” with:

<value>

When I run stak main.scm interactively

And I pipe in the file “input.txt”

Then the exit status should be 0

And the stdout should contain exactly “<value>”.

Examples

value
A
a
~
д
∰
😄

Peek a character

Given a file named “main.scm” with:

(import (scheme base))

(write-char (peek-char))

And a file named “input.txt” with:

<value>

When I run stak main.scm interactively

And I pipe in the file “input.txt”

Then the exit status should be 0

And the stdout should contain exactly “<value>”.

Examples

value
A
a
~
д
∰
😄

Peek a character multiple times

Given a file named “main.scm” with:

(import (scheme base))

(write-char (peek-char))
(write-char (peek-char))

And a file named “input.txt” with:

When I run stak main.scm interactively

And I pipe in the file “input.txt”

Then the exit status should be 0

And the stdout should contain exactly “AA”.

Peek and read characters

Given a file named “main.scm” with:

(import (scheme base))

(write-char (peek-char))
(write-char (read-char))
(write-char (read-char))

And a file named “input.txt” with:

AB

When I run stak main.scm interactively

And I pipe in the file “input.txt”

Then the exit status should be 0

And the stdout should contain exactly “AAB”.

Check if a character is ready or not.

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (char-ready? (open-input-bytevector #u8(<bytes>))) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “<output>”.

Examples

bytes	output
	A
65	A
227 129 130	A
240 159 152 132	A

Read a string

Given a file named “main.scm” with:

(import (scheme base))

(write-string (read-string <count>))

And a file named “input.txt” with “<value>”

When I run stak main.scm interactively

And I pipe in the file “input.txt”

Then the exit status should be 0

And the stdout should contain exactly “<output>”.

Examples

value	count	output
A	0
A	1	A
A	2	A
ABC	2	AB
ABC	3	ABC
ABC	4	ABC
A😄あ	3	A😄あ

Read lines

Given a file named “main.scm” with:

(import (scheme base))

(define (check x)
  (write-u8 (if (equal? (read-line) x) 65 66)))

(check "foo")
(check "bar")
(check "baz")
(check (eof-object))

And a file named “input.txt” with:

foo
bar
baz

When I run stak main.scm interactively

And I pipe in the file “input.txt”

Then the exit status should be 0

And the stdout should contain exactly “AAAA”.

Read a byte vector

Given a file named “main.scm” with:

(import (scheme base))

(parameterize ((current-input-port (open-input-bytevector #u8(<bytes>))))
  (write-u8 (if (equal? (read-bytevector <count>) #u8(<bytes>)) 65 66)))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

bytes	count
	0
1	1
1	2
1 2	2
1 2 3	3
1 2 3	4

Read a byte vector in place

Given a file named “main.scm” with:

(import (scheme base))

(define xs (bytevector <original>))

(read-bytevector! xs (open-input-bytevector #u8(<input>)) <start> <end>)

(write-u8 (if (equal? xs #u8(<output>)) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

original	input	start	end	output

0	1			1
0	1	0		1
0	1	0	1	1
0 0	1 2			1 2
0 0	1 2	0		1 2
0 0	1 2	0	2	1 2
0 0	1 2	0	1	1 0
0 0	1 2	1		0 1
0 0 0 0	1 2 3	1	3	0 1 2 0
0 0 0 0	1 2 3 4	1		0 1 2 3
0 0 0 0	1 2 3 4	1	4	0 1 2 3

original	input	start	end	output
0 0	1 2	0	3	1 2
0 0 0 0	1 2 3 4	1	5	0 1 2 3

Read a value

Given a file named “main.scm” with:

(import (scheme base) (scheme read))

(write-u8 (if (equal? (read) '<value>) 65 66))

And a file named “input.txt” with:

<value>

When I run stak main.scm interactively

And I pipe in the file “input.txt”

Then the exit status should be 0

And the stdout should contain exactly “A”.

Examples

value
#f
#t
0
1
2
42
-1
-2
-42
a
x
foo
#\A
#\newline
“”
“foo”
“Hello, world!”
“\n\r\t”
()
(1)
(1 2)
(1 2 3)
(1 . 2)
(1 2 . 3)
(foo)
(foo bar)
(foo bar baz)
(foo . bar)
(foo bar . baz)
#(foo)
#(foo bar)
#(foo bar baz)
#u8()
#u8(1)
#u8(1 2)
#u8(1 2 3)

Read from a port

Given a file named “main.scm” with:

(import (scheme base) (scheme read))

(write-u8 (if (equal? (read (current-input-port)) 'foo) 65 66))

And a file named “input.txt” with:

foo

When I run stak main.scm interactively

And I pipe in the file “input.txt”

Then the exit status should be 0

And the stdout should contain exactly “A”.

Read a list without a closing parenthesis

Given a file named “main.scm” with:

(import (scheme base) (scheme read))

(read)

And a file named “input.txt” with:

(foo

When I run stak main.scm interactively

And I pipe in the file “input.txt”

Then the exit status should not be 0

And the stdout should contain exactly “”

And the stderr should contain “) expected”.

Read a list without an opening parenthesis

Given a file named “main.scm” with:

(import (scheme base) (scheme read))

(read)

And a file named “input.txt” with:

When I run stak main.scm interactively

And I pipe in the file “input.txt”

Then the exit status should not be 0

And the stdout should contain exactly “”

And the stderr should contain “expression expected”.