Ring Documentation Walkthrough #13 – System Functions

Welcome to the new chapter ‘System Functions‘, this is a very easy chapter.

our functions:

1. system() – exceute a system command.
2. get() – get environment variables like PATH, TEMP .. etc
3. isMSDOS() – check if the operation system is msDOS or not, returns 1 if true, 0 if false
4. isWindows(), isWindows64(), isUnix(), isMacOSX(), isLinux(), isFreeBSD(), isAndroid() – all returns 1 if true, 0 if false
5. windowsNL() – returns the windows’ new line string that contains : CR+LF { char(13) + char(10) }

6. ---

   sysargv – it’s a list contains the command line parameters.

   see sysargv

7. ---

   filename() – returns the active script file name.

---

This is pretty much what we have in the chapter.

see you in the final one.

amrESSAM.

Ring Documentation Walkthrough #12.1 – Advanced Read & Write Files

Hello, We’ll go through some advanced operations about the files.

File Handling:

We will learn in the next example these functions:

• fopen – open a file
• fgets – read a specific amount of a file
• fgetc – read a character of a file
• fexists – check if a file exists
• freopen – re-open a file in a file handler
• fseek ( file_handle, offset, whence ) – set the position of the stream, whence: ( 0=beginning of the file, 1=current position, 2=end of the file)
• rewind – set back the position to the beginning of the file
• fgetpos & fsetpos – get handle of the current position and set new position for the file
• fputc – write a single character
• fputs – write a text
• fwrite – write a text
• fread – read a specific amount of a file
• ftell – know the current position
• fclose – close the file handler
  

  ---

/*
r - read
w - write new or overwrite
a - appends and creates new if doesn't exists
r+ - read & write (update file)
w+ - read & write
a+ - read & append
*/
file = fopen('somewhere.txt', 'r')
see file[1]
see fgets(file, 100) #the same result as above.

see fgetc(file) #returns a character or EOF

see fexists('some_other_file.txt') #returns 0 (false), 1 (true)

file = freopen('some_other_file.txt', 'r+')
fseek(file, 0 , 2) #go to the end of the text file
see ftell(file)
fputc(file, 'a') #append a character
fputs(file, 'amr') #append a text

rewind(file) #set back the position to the beginning of the file.

fwrite(file, 'consider this a something just for the example, ty.') #writes to the file

fread(file, 100) #returns 100 characters from the file

x = fgetpos(file) #returns position handle
fsetpos(file, 5) #set new position of the file
fclose(file) #close the file handler.

---

Temperory files:

There’re two functions for this.

x = tempfile() #returns a file handle for a temp file.
x = tempname() #returns a temp file name that doesn't exists

---

Errors:

• clearerr

  clearerr(file) #clear the EOF error and the error indicators of a stream.
  

• feof

  see feof(file) #returns 1 if it's the end of the file, 0 if it's not.
  

• ferror

  see ferror(file) #returns 1 if there's error indicator, 0 if not.
  

• perror

  perror('error happened') #print error message to the stderr.
  

---

fflush:

We can flushes the output buffer of a stream using the Fflush() function.

fflush(file)

---

ungetc:

We can push a character to the stream using this function so
the character will be available for the next read.

ungetc(file, 'a')

---

Well, at this point we’re done of the files chapter.

see you in the next chapter.

amrESSAM.

Ring Documentation Walkthrough #12 – Files

Welcome to the new chapter, we will discuss today some of the files functions.

This part is easy to understand.

• Read()
  This function basically reads the content in a file and returns it as a string.
  For an example:

  content = read('info.txt')
  see content
  content_exe = read('chrome.exe')
  see content_exe
  

• ---

  Write()
  You can use this function to write string or binary files.

  content = 'Surrender'
  write('message.txt', content)
  

  We can using it in copying files too:

  pdf1 = read('ringdoc.pdf')
  pdf2 = write('ringdoc2.pdf', pdf1)
  

• ---

  Dir()
  It basically returns all the files & sub directories found in a directory.
  It returns a list format, every item in the list is actually a list contains two items : 1- file/sub directory name, 2- Type (0 for File, 1 for Directoy)

  tree = dir('folder')
  for item in tree
     see item[1] #output: the file/directory name
     if item[2] = 0 see 'File' + nl
     but item[2] = 1 see 'Directory' + nl
     ok
  next
  

• ---

  Rename()

  rename('tweeter.ico', 'twitter.png')

• ---

  Remove()
  For deleting files.

  remove('setup.exe')
  

---

That’s it, next part i will discuss some of the left functions.

See you in the next one.

amrESSAM.

Ring Documentation Walkthrough #11 – Math

Welcome to the new Chapter, we’ll talk about the mathematical functions.

First of all, the list of the main functions are here, i won’t include them in the post because they’re easy to understand.

So, there’re 3 small functions left.

1. Random()

   see random() #output: random number
   see random(100) #output: random number <= 100
   see random(10) #output: random number <= 10
   

2. Unsigned()

   see unsigned(5, 10, '+') #output: 15
   see unsigned(5, 10, '*') #output: 50

3. Decimals()

   see 5.12345 + decimals(3) #output: 5.123
   see 5.12345 + decimals(2) #output: 5.12
   

 

---

Yeah, This is all about the mathematical functions in Ring.

See you in the next chapter.

amrESSAM.

Ring Documentation Walkthrough #10 – Check Data Types 1

Welcome to the chapter 10, you’ve made a lot of progress.

We will learn in this post five important functions for checking types of objects, and they’re :

• isString() & isNumber()

  see isString('amr') #output: 1 (true)
  see isString(1) #output: 0 (false)
  see isNumber(1) #output: 1 (true)
  

• isList()

  see isList( [1, 2, 3] ) #output: 1 (true)
  see isList( 'amr' ) #output: 0 (false)
  

• isNull()

  x = ''
  see isNull(x) #output: 1 (true)
  see isNull('NULL') #output: 1 (true)
  see isNull(2) #output: 0 (false)
  see isNull( [1, 2, 3] ) #output: 0 (false)
  see isNull('Null') #output: 0 (false)
  

• type()

  see type( 'amr' ) #output: STRING
  see type(1) #output: NUMBER
  see type( [1, 2, 3] ) #output: LIST
  see type('') #output: STRING
  see type('NULL') #output: STRING
  see type(true) #output: NUMBER, because true equals 1
  see type(false) #output: NUMBER, because false equals 0
  

Will be continued in the next post …

amrESSAM.

Ring Documentation Walkthrough #9 – Date and Time

We’ll talk in this chapter about the Date and Time in Ring and its functions.

Let’s start.

---

clock():

We use this function to know how long the program spent running.

for x = 1 to 1000000
   see clock() + nl
next
#output: milliseconds in each line.

---

time():

We can get the local system time using this function.

for x = 1 to 1000000
   see time() + nl
next

---

date():

We can get the local date with this. The format is dd/mm/yyyy

see date()

---

timelist():

This one returns a list of date and time information.

see timelist()

This table shows you index of each info.

• 1 – Abbreviated weekday name.
• 2 – Full weekday name.
• 3 – Abbreviated month name.
• 4 – Full month name.
• 5 – Date & Time.
• 6 – Day of the month.
• 7 – Hour in 24 format.
• 8 – Hour in 12 format.
• 9 – Day of the year.
• 10 – Month of the year.
• 11 – Current minutes.
• 12 – AM or PM.
• 13 – Current seconds.
• 14 – Week of the year.
• 15 – Day of the week.
• 16 – Date.
• 17 – Time.
• 18 – Year of the century.
• 19 – Year.
• 20 – Timezone.
• 21 – Percent sign.

Example:

see timelist()[2] + nl #output: Full weekday name.
see timelist()[19] + nl #output: Year.
see timelist()[6] + nl #output: Day of the month.

---

addays() & diffdays():

see 'Current date : ' + date() + nl #output: 13/02/2016
see 'After 10 days : ' + adddays( date(), 10 ) #output: 23/02/2016

Date1 = date()
Date2 = adddays(Date1, 10)

see diffdays(Date1, Date2) #output: Date1 - Date 2 = -10
see diffdays(Date2, Date1) #output: Date2 - Date1 = 10

---

This is pretty much the date and time in Ring.

See you in the next chapter.

amrESSAM.

Ring Documentation Walkthrough #8.3 – substr()

We can do a lot with this function:

1. Find Substring position.

   see substr('Al Ahly SC', 'Ahly') #output: 4

2. Get string from specific position to the end.

   position = substr('Al Ahly SC', 'Ahly')
   see substr('Al Ahly SC', position) #output: Ahly SC
   

3. Get specific amount of characters from specific position.

   str = 'Al Zamalek SC'
   position = substr(str, 'Zamalek')
   see substr(str, position, 7) #output: Zamalek
   

4. Replace words or characters inside a string.

   str = `Social Network`
   see substr(str, 'Network', 'Life') + nl #output: Social Life
   
   #Ignore the case by adding the parameter 1 will convert the string to lower case.
   see substr(str, 'network', 'life', 1) + nl #output: social life 
   

---

 

DONE!, This is the end of the strings chapter, see you in the new chapter.

amrESSAM.

Ring Documentation Walkthrough #8.2 – strcmp()

We can compare two strings using this function.

This is the example from the official documentation and the explanation by Eng. Mahmoud Fayed.

see strcmp ('hello', 'hello') + nl #output: 0, the two strings are typical.

see strcmp ('a', 'b') + nl #output: -1, the 'a' letter in ASCII is 97, 'b' in ASCII is 98, then 'a' < 'b' and the output is -1 

see strcmp ('b', 'a') + nl #output: 1, because 'b' > 'a' in ASCII.

---

But, in case you just want to see if the strings are the same or not we can do this:

give str

if strcmp (str, 'hello') = 0
   see `The string you entered does match.`
else
   see `The string you entered doesn't match.`
ok

NOTE: In the if statement here, we use only one = not == like in the other languages.

Then test it:

input: hello
output: The string you entered does match.
input: Hello
output: The string you entered doesn't match.

This is basically how it is done.

See you in the next post.

amrESSAM.

Ring Documentation Walkthrough #8.1 – str2list & list2str

We can convert strings to lists and the opposite using str2list & list2str functions.

str = `Step 1
Step 2
Step 3`
list_of_string = str2list (str)
see type(list_of_string) #output: LIST
see list_of_string

string_of_list = list2str (list_of_string)
see type(string_of_list) #output: STRING
see string_of_list

This is how we use these functions.

See you in the next post of strings.

amrESSAM.

Ring Documentation Walkthrough #8 – Strings

Welcome to the new Chapter, strings.

Let’s start by declaring a string variable, there’re 4 ways to do it:

x = 'LIGO detects first ever gravitational waves.' # using '
x = "LIGO detects first ever gravitational waves." # using "
x = :LIGOdetectsfirstevergravitationalwaves # using : operator
x = `LIGO detects first ever gravitational waves.` #we can use " & ' normally inside this type of strings.

For more about the operators in Ring go check this link here

---

Access String Letters:

device = 'iPhone'
see device[1] #output: i
see device[2] #output: P
see device[3] #output: h
see device[4] #output: o
see device[5] #output: n
see device[6] #output: e

NOTE: The index in Ring starts from 1 not 0 like the other languages.

---

Get the length of a string:

Do it just like the pythonic way.

device = 'iPhone'
see len(device) #output : 6

---

Upper & Lower cases:

rip = 'rip'
see upper(rip) + nl #output RIP
see lower(rip) + nl #output rip

---

Left & Right functions:

We can get specific amount of text of a variable from the left or the right by using these functions:

Hello = `Hello, It's me.`
see left(Hello, 5) + nl #output : Hello
see right(Hello, 3) + nl #output : me.

NOTE: I used ` in declaring the string variable, it helps when the string contains ‘ and “.

---

Trim() Function:

I guess you already know what it does.

str = `  don't erase me.  `
see trim(str) #output : don't erase me.

---

Copy() function (duplicating a string):

We can duplicate a string more than once using this function.

x = 'Bla '
see copy(x, 3) #output : Bla Bla Bla

---

Lines() function:

When you have a multi-line string, you can know its lines count.

x = 'Apple
Google
Samsung'
see lines(x) #output : 3

---

We’re done here, i hope the examples were clear enough.

See you in the next post.

amrESSAM.