add operation

Signed-off-by: Shulin <wangwangwar@gmail.com>
add stream operations and tests

Signed-off-by: Shulin <wangwangwar@gmail.com>
simple delay-force impl

Signed-off-by: Shulin <wangwangwar@gmail.com>
add true and false definition, because guile use #t and #f instead

Signed-off-by: Shulin <wangwangwar@gmail.com>
Infinite stream, but because our scheme impl is not *lazy*, infinite stream may cause problems.

Signed-off-by: Shulin <wangwangwar@gmail.com>
Define delay in a special way, *define-syntax*, from web

Signed-off-by: Shulin <wangwangwar@gmail.com>
Add executable permission

Signed-off-by: Shulin <wangwangwar@gmail.com>
Basic scheme impl

Signed-off-by: Shulin <wangwangwar@gmail.com>
ex4.2's solution

Signed-off-by: Shulin <wangwangwar@gmail.com>