# Utility Functions

#### Zhengjia Wang

    library(dipsaus)

#### 1. Cat strings with levels: `DEBUG`, `INFO`, `WARNING`, `ERROR`, and `FATAL`

    cat2('Debug passed!', level = 'DEBUG')
    #> ✔ Debug passed!

    cat2('You are all set.', level = 'INFO')
    #> ♥ You are all set.

    cat2('Wait a second...', level = 'WARNING')
    #> ⚠ Wait a second...

    cat2('Ooops', level = 'ERROR')
    #> ✖ Ooops

    cat2('Bi--Doop---', level = 'FATAL')
    #> ✖ Bi--Doop---
    #> Error:
    #> ...

Level `FATAL` will raise errors.

#### 2. `parse_svec` and `deparse_svec`

`parse_svec` converts characters like `"7-10,14-15"` to numeric vectors

    parse_svec("7-10,14-15")
    #> [1]  7  8  9 10 14 15

`deparse_svec` reverse the process

    deparse_svec(c(2,5,3,1,7))
    #> [1] "1-3,5,7"

Parameter `max_lag` in `deparse_svec` changes the threshold of integers collapsed together:

    deparse_svec(c(1,2,4,7,11))
    #> [1] "1-2,4,7,11"

    deparse_svec(c(1,2,4,7,11), max_lag = 2)
    #> [1] "1-4,7,11"

    deparse_svec(c(1,2,4,7,11), max_lag = 3)
    #> [1] "1-7,11"

#### 3. System Information

The goal is to work as an alternative to retrieve system information. For example, R doesn’t provide functions to get memory limits, or CPU chip-set information on Linux or MacOS.

    # Total RAM in bytes
    get_ram()
    #> 17179869184.0 B

    # Print-friendly
    to_ram_size(get_ram(), 1024)
    #> 16.0 GB

    # WARNING: $free is the total RAM - R usage, is no the actual free RAM
    mem_limit2()
    #> $total
    #> 17179869184.0 B
    #> $free
    #> 17120491128.0 B

#### 4. Interactive Questions

`askYesNo` comes with `utils` package allows to ask yes/no questions and returns logical value. If `cancel` is entered, then the function returns `NA`, if answers other than `yes`, `no` or `cancel` is given, it raise an error. `dipsaus::ask_yesno` will ask the question again and again until the user actually say `yes` or `no`

    > ask_yesno('Please answer an yes/no question, ok?')
    ## ♥ Please answer an yes/no question, ok? (Yes/no):
    > qweee
    ## ⚠ Please answer Y/yes, N/no, or c to cancel. (Yes/no):
    > ttt
    ## ⚠ Please answer Y/yes, N/no, or c to cancel. (Yes/no):
    > y
    ## [1] TRUE

`ask_or_default` instead of asking a yes/no question, it asks a question with default answer. User don’t have to type the answers if the they accept defaults:

    > ask_or_default("What is your password", default = 'I will not tell you!')
    ## ♥ What is your password
    ##   [default is ‘I will not tell you!’]
    >
    ## [1] "I will not tell you!"