Data types

BDS is a statically typed language that has simple data types. The intention is to avoid runtime errors.

The usual basic types are defined and bds also offers extensible data types (classes).

Type	Meaning
string	A string (same a Java's String)
int	A 64 bit integer number (same a Java's long)
real	A 64 bit IEEE 754 number (same as Java's double)
bool	A boolean value, can be 'true' or 'false' (same as Java's boolean)
Arrays, List, Stacks	These are all the same, just a different way to call a list of elements
Maps	Maps are hashes (a.k.a. dictionaries that have string keys.
Class	An object definition

Strings

There are several basic methods defined for strings:

Return type	Method / Operator	Meaning
string	s = s1 + s2	Concatenate strings.
string	s += s2	Append to string.
bool	string.endsWith(string str)	True if string ends with str
bool	string.isEmpty()	True if the string is empty
int	string.indexOf(string str)	Index of the first occurrence of str in string
int	string.lastIndexOf(string str)	Index of the last occurrence of str in string
int	string.length()	String's length
string	string.replace(string str1,string str2)	A new string replacing 'str1' with 'str2'
bool	string.parseBool()	Parse a bool
int	string.parseInt()	Parse an int number
real	string.parseReal()	Parse a real number
string[]	string.split(string regex)	Split using a regular expression
bool	string.startsWith(string str)	True if string starts with str
string	string.substr(int start)	Substring from start to end of string
string	string.substr(int start,int end)	Substring from start to end
string	string.toLower()	Return a lower case version of the string
string	string.toUpper()	Return an upper case version of the string
string	string.trim()	Trim spaces at the beginnig and at the end

Strings as files

Strings can be used in several different ways. For instance, it is common that a string can represent a file name (path) in a script. So you can use 'file' related methods on string. E.g.:

string f = "in.txt"
if( f.canRead() ) {
    print (" Can read file $f\n" )
}

Here f is a string, but it has a method canRead() which returns true if f is a file and it can be read.

String (as file) methods

Return type	Method	Meaning
string	string.baseName()	File's base name
string	string.baseName(string ext)	File's base name, remove extention 'ext'
string	string.download()	Donwload data from URL (string). Returns local file name (empty string if failed)
bool	string.download(string file)	Donwload data from URL to 'file'. Returns true if succeeded.
bool	string.canRead()	True if file has read permission
bool	string.canWrite()	True if file has write permission
bool	string.canExec()	True if file has execution permission
void	string.chdir()	Change current directory
bool	string.delete()	Delete file
string[]	string.dir()	List files in a directory ('ls')
string[]	string.dir(string regex)	List files matching a 'glob' (regular expression for files)
string	string.dirName()	File's directory name
string[]	string.dirPath()	List files using canonical paths
string[]	string.dirPath(string regex)	List files, matching a 'glob' (regular expression for files), using canonical paths
string	string.extName()	File's extension
bool	string.exists()	True if file exists
bool	string.isDir()	True if it's a directory
bool	string.isFile()	True if it's a file
bool	string.mkdir()	Create dir ('mkdir -p')
string	string.path()	Absolute path to file
string	string.pathCanonical()	Canonical path to file
string	string.pathName()	Absolute dir
string	string.read()	Read the whole file into a string
string[]	string.readLines()	Read the whole file and split the lines
string	string.removeExt()	Remove file extension
string	string.removeExt(string ext)	Remove file extension, only if it matches the provided one
bool	string.rm()	Delete a file
string	rmOnExit()	Delete file when current thread finishes execution (assumes string is a file path)
string	rmOnExitCancel()	Cancel previous 'rmOnExit' for file
int	string.size()	File size in bytes
string	string.swapExt(string newExt)	Swap file extension
string	string.swapExt(string oldExt,string newExt)	Swap file extension, only if extension matches the provided 'oldExt'
string	string.upload()	Upload data to URL (string). Returns true if succeeded.
bool	string.upload(string file)	Upload data from 'file' to URL. Returns true if succeeded.
string	string.write(string file)	Write string to 'file'

Strings as tasks

Strings can also be used to refer to tasks. When a task is created, the task expression returns a task ID, which is a string. This task ID can be used for task operations, for instance:

tid := task echo Hello
wait tid

Here the wait statement will wait until the task "echo Hello" finishes executing.

More task related methods:

Return type	Method	Meaning
bool	string.isDone()	True if the task finished
bool	string.isDoneOk()	True if the task finished without errors
string	string.stdout()	A string with all the STDOUT generated from this task
string	string.stderr()	A string with all the STDERR generated from this task
int	string.exitCode()	Exit code
string[]	getTasksDone()	Return a list of all task IDs that have finished (either succesfully or with errors)
string[]	getTasksRunning()	Return a list of all task IDs that are running
string[]	getTasksToRun()	Return a list of all task IDs that have not yet started to run (e.g. waiting to be executed)

Arrays, List, Stacks

Arrays, list and stacks are all the same thing. You can create a list of strings simply by declaring:

string[] arrayEmpty
string[] array = ["one", "two", "three"]

Similarly, a list of ints is just

int[] listIntEmpty
int[] primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]

Methods

Returns	Method	Meaning
+=	Append element(s) at the end of the list
Element added	add(X)	Add X to the end of the list
Element added	add(int idx,X)	Add X to position idx in the list
Same list	delete()	Delete all files in the list (assumes list elements are file names). Same as list.rm()
int	count(X)	Count number of occurrences of X in the list
bool	has(X)	Does the list contain X?
First element	head()	Get first element
int	indexOf(X)	Position of element X in the list
bool	isEmpty()	'true' if the list is empty
string	join()	A string joining all elements of the list (separator ' ')
string	join(string sep)	A string joining all elements of the list (separator 'sep')
Last element	pop()	Get last element and remove it from the list
Element pushed	push()	Add at the end of the list
Element to remove	remove(X)	Remove element X from the list
Element to remove	removeIdx(int idx)	Remove element at position idx from the list
New reversed list	reverse()	Create a new list and reverse it
Same list	rm()	Delete all files (assumes list elements are file names)
Same list	rmOnExit()	Delete all files when current thread finishes execution (assumes list elements are file names)
Same list	rmOnExitCancel()	Cancel previous 'rmOnExit' for all files
int	size()	Return the number of elements in the list
New sorted list	sort()	Create a new list sorting the elements of this list
List	tail()	Create a new list with all but the first element

Iterating on an array/list You can iterate on an array simply by doing

$ cat z.bds 
string[] array = ["one", "two", "three"]

for( string val : array ) { print("Value: $val\n") }

$ bds /z.bds
Value: one
Value: two
Value: three

Maps

Maps are hashes that have string as keys. You can create a map simply by declaring:

string{} mstr    # This maps string keys to string values

mstr{"Hello"} = "Bye"
mstr{"Bonjour"} = "Au revoir"
mstr{"Hola"} = "Adios"

or a map of real numbers

real{} mre   # This maps string keys to real values
mre{"one"}   = 1.0
mre{"two"}   = 2.0
mre{"e"}     = 2.7182818
mre{"three"} = 3.0
mre{"pi"}    = 3.1415927

Methods

Returns	Method	Meaning
bool	hasKey(string key)	True if the key is in the map
bool	hasValue(value)	True if 'value' is in the map
list	keys()	A sorted list of all keys in the map
bool	remove(key)	Remove key from this map
int	size()	Number of elements in this map
list	values()	A sorted list of all values in the map

Iterating on a map You can iterate over all values in a map, simply by doing

$ cat z.bds 
string{} mstr = { "Hello" => "Bye", "Bonjour" => "Au revoir", "Hola" => "Adios" }

for(string v : mstr ) { 
   print("Values : $v\n") 
}

$ bds z.bds
Values : Adios
Values : Au revoir
Values : Bye

If you want to iterate on keys instead of values, you can do this:

$ cat z.bds 
string{} mstr = { "Hello" => "Bye", "Bonjour" => "Au revoir", "Hola" => "Adios" }

for(string k : mstr.keys() ) { 
    print("Key : $k\tValue : " + mstr{k} + "\n") 
}

$ bds z.bds
Key : Bonjour    Value : Au revoir
Key : Hello    Value : Bye
Key : Hola    Value : Adios