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Statements and Declarations

SQeeL script consists of following statements and declarations.

Declaration

Control structure

Expression

Label

Command

* Refer to SQeeL Manual -CGI- and SQeeL Manual -DB- for details.

Empty statement

Empty statement consists of tab, space, line feed, and comment only.

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Comment

Comment can be used when you want to add notes to a source program as a comment.
Following three signs are currently available for SQeeL.

Comment signs
//	All lines after double slash (//) are considered as comment.
#	Lines starting with a pound sign (#) are considered as comment.
/* */	Lines enclosed in slash and asterisk (/* */) are considered as comment. Multiple lines can be enclosed at a time.

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Indent

SQeeL allows you to leave blank space in a script program, which makes it easier to read a program.

Example: indented program

/* Call a function to calculate the power and print out */
print(beki(2, 3)) 	// Calculate the third power of 2
exit
function beki(a, b)
	local ans = 1, i
	loop i = 1; i <= b; i++
		ans = ans * a
	endloop
	return ans
endfunction

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Other

Basically, SQeeL script is described in a single line but allows you to extend the script in two or more lines.
If you extend the script over multiple lines, enter a backslash at the end of the current line and continue the script in the next line. (Use yen mark if your machine is in Japanese environment.)

Example: script extends over multiple lines

traceout = stderr		// Output an error of trace.
global f1, f2
f1 = open \
('test1.dat', new)	// A script extents over two lines.
f2 = open('test2.dat', new)
print('4567')
output(f1)
print('0123')
close(f1)
close(f2)

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Name consists of a single letter or more used for function name, variable name, and label name.
Letters, numbers, and underscore (_) are available as name.
Name must always start with a letter.
You cannot use the user-defined function name, variable name, and label name same as system function name, system variable name, and reserved word.
Name is not case-sensitive.

Example: Names
a1
a_12
const_user

Example: Invalid names
1a	Name starts with a number.
_a12	Name starts with an underscore.
const	Reserved word is used.

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SQeeL has four built-in datatypes as follows.

Integer
Real Number
String
Array

Integer

Integers between -2147483647 and 2147483647 are treated as integer type and are described in hexadecimal, octal, and decimal representations in literals.
Decimal representation uses negative number and number.
Hexadecimal representation uses 0 to F and uses 0x as a prefix.
Octal representation uses 0 to 7 and uses 0 as a prefix.
Hexadecimal and octal representations are converted to decimal before being output.

Example: Integer literal
543 0 -101	Decimal
0xFF00	Hexadecimal
0733	Octal

To assign integer datatype to a variable, use an assignment statement.
Integer itself is assigned to the variable.

Example: Assignment statement

value = 100

value = 100		Name	Data area
		value	100 (Integer)

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Real Number

-308th to 308th power of 10 is considered as real number.
Real number literal consists of fixed-point part and exponent part.
Fixed-point part is written by using negative sign and decimal point. Exponent part, on the other hand, is written by using the negative sign and numbers followed by E.

Example: Real number literal
-1.666E5 -1.666E-5	Fifth power of 10 of -1.666 Minus fifth power of 10 of -1.666
0.5 .725 -3.14	Fixed-point part can be excluded.

To assign real number datatype to a variable, use an assignment statement.
Real number itself is assigned to the variable.

Example: Assignment statement

value = -123.5

value = -123.5		Name	Data area
		value	-123.5 (real number)

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String

Letters can be treated as string.
String literals are enclosed in either single quotes or double quotes.

Example: String literal
"ABCDEFG"	ABCDEFG
'ABCDEFG'	ABCDEFG
"ABC'DEFG"	ABC'DEFG	Single quotation marks shown as string
'ABC"DE"FG'	ABC"DE"FG	Double quotation marks shown as string

Some letters do not allow to be used as string literals.
In this case, use a backslash (yen mark in Japanese) as an escape letter.
If you write the character code in the string, add two digits hexadecimal after the backslash and three digits octal after the yen mark.
Following letters are called escape sequence containing specific significance.

Example: Escape sequence
¥n	Newline
¥t	Tab
¥r	Return
¥f	Form feed
¥"	Double quotation is shown as letter.

Example: String literals using the escape sequence
"¥x41¥x42"		AB
"¥101¥102"		AB
"ABC¥"DEFG"		ABC"DEFG
"ABC¥¥DEFG"		ABC¥DEFG
"ABC¥nDEF"		ABC DEF

String literal can contain an expression.
Sections enclosed between ${ and } are considered as the expression. The result of the expression is replaced with the letter.

Example: String literal with the expression
"1 + 1 = ${ 1 + 1 }"		1 + 1 = 2

To assign string datatype to a variable use an assignment statement.
Reference to the string literal data is input in the variable.

Example: Assignment statement
string = 'ABC'

string = 'ABC'	Name	Data area
	string	Reference to the character code

		ABC

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Array

Multiple data can be managed as a single data.
A group of data is called an array, and each data is called an element of the array.
Each element is numbered in an ascending order starting with 0.
The element contains any one of integer, real number, or string.
There are two methods of writing the array literal, all elements or number of elements and initial value.

All elements
Elements are separated by comma in a section enclosed between { and }.
Following example indicates that integer 1 is numbered as 0, integer 2 is numbered as 2, and string abc is numbered as 3.

Array literal with all elements
{1, 2, "abc"}

{1, 2, "abc"}	0	1 (integer)
	1	2 (integer)
	2	“abc” (string)

Number of elements and initial value
Number of elements and the initial value are separated by comma in a section enclosed between { and }.
Following example indicates that element numbers 0 to 4 represent the string abc.

Array literal with number of elements and initial value
{4 : "abc"}

{4 : "abc"}	0	“abc” (string)
	1	“abc” (string)
	2	“abc” (string)
	3	“abc” (string)

To assign integer datatype to a variable, use an assignment statement.
When the array datatype is assigned, the array is copied, and then reference to this copy is entered as a variable.
Enclose the element of the assigned array between [ and ] to specify the element number.

Assign the array as a variable
Value = {5 : 1024}	Create an array with five elements, and assign an integer 1024 to every element.

Specify the element of the array
value[2]	Specify a value with an element number 2 from the array value.

value = {5:1024}		0	1024 (integer)
		1	1024 (integer)
		2	1024 (integer)
		3	1024 (integer)
		4	1024 (integer)
			Copy
Name	Data area	Array
value	Reference to the string	0	1024 (integer)
		1	1024 (integer)
		2	1024 (integer)
		3	1024 (integer)
		4	1024 (integer)

You can assign all datatypes to the element of the array.
You can also use the multidimensional array.
If the array is assigned to the element with the array and you want to clarify the element of the assigned array, enclose the element of the assigned array between [ and ].

Two-dimensional array
value = { 3 : { 2 : 1024 } }	Create an array with two elements in an array with three elements, and assign an integer 1024 to every element.

Specify the element of the two-dimensional array
value[2][1]	Specify a value with the element number 1 from the array with the element number 2 of multi-dimensional array value.

value = { 3 : { 2 : 1024 } }	0	0	1024 (integer)
	0	1	1024 (integer)
	1	0	1024 (integer)
	1	1	1024 (integer)
	2	0	1024 (integer)
	2	1	1024 (integer)

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Associative array

Associative array is not a common array.
Associative array enables you to name each element of the array.
Likewise the array literal, elements in the associative array are separated by comma and enclosed between { and }. The associative array enables you to connect the string that is a key of the associative array to its value by using a mark =>.

Associative array literal

{'my age' => 32, 'my weight' => 50, 'my status' => 'okey'}

	{'my age' => 32, 'my weight' => 50, 'my status' => 'okey'}

	'my age'	32 (integer)
	'my weight'	50 (integer)
	'my status'	"okey" (string)

Following format is not allowed.

Invalid associative array literal

{ 5 : 'my age' => 32 }

You can use the string to access the element of the associative array.
You can also access the element by using the number because the element is numbered in order of the appearance of the key string.
For example, the element of my age above is 0th.

If you assign the associative array datatype to a variable, refer to other arrays for further instruction. When you access the element, use the key string.

Access associative array literal

value['my age'] = 32

You can increase the element dynamically.
Specify new key string and then assign it to add an element.

		'my age'	32 (integer)
		'my weight'	50 (integer)
		'my status'	"okey" (string)
'my height'	180	'my height'	180 (integer)

Other types of array can automatically be changed to the associative array by simply adding the key string.
If there is an element of which the key is not specified to an array and you specify the new string, keys are allocated to the element without any key first.

Array and associative array

value = { 1 : 0 }
value['my age'] = 32

'my age'	32	'my age'	32 (integer)
		(1)	0 (integer)
		(2)	0 (integer)

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Variable scope

Normally, variables are declared in a declaration before actually being used. Variable scope varies according to the type of declaration.
Variables do not have to be declared. If non-declared variables are used in a function, these variables are considered as local variable. If non-declared variables are used in any section other than the function, these variables are considered as global variable.
If there are variables not declared in a source file, alert messages are logged when a file is converted to a binary file.
If a variable is referred to before a value is not assigned to the non-declared variable, an error occurs and a program stops being executed.

Variable scope

Exglobal scope

File A

global, const variable scope

Function A-1

Local variable scope

Function A-2

Local variable scope

File B

global, const variable scope

Function B-1

Function B-2

Fixed number is a value effective for entire source file declared in const statement, and can be referred to by any sections in the same source file. However, it is not allowed to rewrite the fixed number.
Fixed numbers are allocated at the time when a program is read by memory.
Fixed number can be declared in any location in the source file.

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global variable

global variable is effective in entire source file declared in global statement and can be referred to or assigned to by any function in the same source file.
Likewise const statement, global variable can be declared in any location in the source file.
Global variable is allocated at the time when a program is read by memory.
If you want to initialize the declaration and the initialization of variable in a single row, you can write a fixed number but you cannot write an expression using functions and variables.
Global declaration can be assigned, but const statement is for reference only.

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exglobal variable

exglobal variable can be treated as a common variable in the source file and also be effective outside of the source file.
exglobal variable can be referred to and assigned to the same variable between multiple files. In order to do so, exglobal variable needs to be declared in each file using exglobal variable.

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Expression

Expression consists of non-operator literal, variable, function call, and operator.
The expression always returns the result.
Operators are prioritized and calculated in descending order of priority.

Calculate in descending order of priority

1 + 2 * 3

In this case, 2 is multiplied by 3 first, and then its result is added to 1.

Operator with same priority

1 + 2 + 3

In this case, 1 is added to 2 first, and then its result is added to 3.
Use ( ) to change the order of priority. If the expression contains a section enclosed in ( ), numbers enclosed in ( ) are calculated first.

Expression with ()

( 1 + 2 ) * 3

In this case, 1 is added to 2 first, and then its result is multiplied by 3.

Arithmetic operation

There are two types of arithmetic operations, binominal operation and unary operation.
Binominal operation contains two non-operation values. Unary operation, on the other hand, contains a single non-operation value.

1 + 2	Binominal operation
i++	Unary operation

Arithmetic operation may return different results when calculating as integer or calculating as real number.
Thus, it is necessary to determine integer or real number by non-operation datatype.
If non-operation value does not contain real number, it is calculated as integer.
If non-operation value contains real number, it is calculated as real number.
If it is calculated as integer, all non-operation values are converted to integer.
If it is calculated as real number, all non-operation values are converted to real number.
Arithmetic operation returns a value.
When calculated as real number, real number is returned. When calculated as integer, integer is returned.

Integer and real number and datatype
1 + 2	Return an integer	（=3）
1.0 + 2.0	Return a real number	（=3.0）
1.0 + 2	Return a real number	（=3.0）

Following are the list of operations.
Operator with a larger priority value is calculated first.
Expr1 and expr2 represent non-operator values, and var indicates it is available only when an non-operator value is variable.

Arithmetic operator
operator	priority	method	description
+	5	expr1 + expr2	Return a sum of expr1 and expr2
-	5	expr1 - expr2	Return a value of expr2 subtracted from expr1
*	6	expr1 * expr2	Return a product of expr2 and expr1
/	6	expr1 / expr2	Return a quotient of exprt1 divided by expr2
%	6	expr1 % expr2	Return a reminder of exprt1 divided by expr2
=	1	var = expr1	Assign expr1 to var, and return a value assigned to var.
+=	1	var += expr1	Assign the sum of var and expr1 to var, and return a value assigned to var.
-=	1	var -= expr1	Assign a difference of expr1 subtracted from var, and return a value assigned to var.
*=	1	var *= expr1	Assign a power of var and expr1 to var, and return a value assigned to var.
/=	1	var /= expr1	Assign a quotient of var divided by expr2 to var, and return a value assigned to var.
++	8	++var	Assign a value of 1 added to var to var, and return var.
++	8	var++	Assign a value of 1 added to var to var, and return the source value of var.
--	8	--var	Assign a value of 1 subtracted from var, and return var.
--	8	var--	Assign a value of 1 subtracted from var, and return the source value of var.
-	7	- expr1	Returns a power of expr1 and -1.

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String Operator

String Operator returns string datatype.
Non-operators are converted to string datatype, and are determined.

String operator
Operator	Priority	Method	Description
&	4	expr1 & expr2	eturns a string with expr2 connected after expr1.
=	1	var = expr1	Assigns expr1 to var, and returns a value assigned to var.

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Arithmetic non-operator

Arithmetic non-operator returns logical value (true and false).
Logical value is not a datatype supported by SQeeL. Thus, when the result is true, it returns 1, and 0 when it is false.
Non-operators of arithmetic non-operator are converted before calculation.

Arithmetic non-operator
Operator	Priority	Method	Description
>	2	expr1 > expr2	Returns true if expr1 is greater than expr2. Otherwise, returns false.
<	2	expr1 < expr2	Returns true if expr1 is numerically less than expr2. Otherwise, returns false.
>=	2	expr1 >= expr2	Returns true if expr1 is numerically greater than or equal to expr2. Otherwise, returns false.
<=	2	expr1 <= expr2	Returns true if expr1 is numerically less than or equal to expr2. Otherwise, returns false.
==	2	expr1 == expr2	Returns true if expr1 is numerically equal to expr2. Otherwise, returns false.
!=	2	expr1 != expr2	Returns true if expr1 is numerically not equal to expr2. Otherwise, returns false.

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String comparison operation

String comparison operation returns logical value (true and false.)
Non-operators of the string comparison operator are converted to string.

String comparison operator
Operator	Priority	Method	Description
EQ	2	expr1 EQ expr2	Returns true if expr1 is equal to expr2. Otherwise, returns false.
NE	2	expr1 NE expr2	Returns true if expr1 is not equal to expr2. Otherwise, returns false.
GT	2	expr1 GT expr2	Compares expr1 with expr2 in character code. Returns true if expr1 is greater than expr2. Otherwise, returns false.
GE	2	expr1 GE expr2	Compares expr1 with expr2 in character code. Returns true if expr1 is equal to or greater than expr2. Otherwise, returns false.
LT	2	expr1 LT expr2	Compares expr1 with expr2 in character code. Returns true if expr1 is smaller than expr2. Otherwise, returns false.
LE	2	expr1 LE expr2	Compares expr1 with expr2 in character code. Returns true if expr1 is equal to or smaller than expr2. Otherwise, returns false.
LIKE	2	expr1 LIKE expr2	Compares a pattern of expr1 with expr2. Returns true if the patterns match. Otherwise, returns false. Percentage mark (%) and underscore (_) are available as a wildcard. % indicates 0 or more of any letters match. _ indicates 1 or more of any letters match. If you want to use % and _ as a letter, add a pound sign (#) before % and _.
MATCH	2	expr1 MATCH expr2	Compares string of expr1 with regular expression of expr2. Returns matched string as true. Otherwise, returns false.

Regular expressions available for MATCH
+	Match 1 or more times
*	Match 0 or more times
?	Match 1 or 0 times
.	Match any character
\	Escape letter
^	Match the beginning of the line
$	Match the end of the line
rx1 \| rx2	Connect two regular expressions rx1 and rx2 with OR condition.
{m[,n]}	Specify the number of times the regular expression is repeated. If m is specified, matches m times. If m and n are specified, matches m times but not more than n times.
(rx1)	Subpattern the regular expression rx1.
[class_list]	Match the string class. List the element composing string class in class_list. When ^ is placed before class_list, match any other elements than the ones listed in class_list. Elements consist of letters or following descriptions.
	s-e	Specify the range of strings. Specify [0-9] to match any string between 0 and 9.
	[.str.]	Consider str specifying an element of multiple strings as a single element of string class. Specify [[.ce.]]* to match 0 times or more of ce.
	[:cname:]	Match string class shown in cname. Following can be specified in cname. Specify [[:alpha:]] to match 0 times or more of alpha.
		alpha	Alphabet
		graph	Any alphanumeric or punctuation character
		space	Space
		blank	Space and tab
		lower	Lower-case character
		upper	Upper-case character
		cntrl	Any control character
		print	Any alphanumeric or punctuation character or space
		digit	Any decimal digit
		xdigit	Any hexadecimal digit

Example of regular expression program

if matched = "The quick brown fox jumped over the lazy dog" match \
		"([[:alpha:]]*o[[:alpha:]]*)([[:alpha:]]*)([[:alpha:]]*o[[:alpha:]]*)"
	loop i = 0; i < count(matched); i++
		print(matched[i])
	endloop
endif

Result:
fox jumped over

The example above uses match operator to match a pattern of string, refers to a variable matched in loop statement, and prints out a value.

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Logic Operation

Logic operation returns a logical value.
Non-operators of logic operation are converted to logical value before calculation.
0 indicates false and any value other than 0 indicates true for integer and real number.
0 string indicates false and any string other than 0 indicates true for string.
Following is a list of operators for logic operation.

Logic operation
Operator	Priority	Method	Description
and	3	expr1 and expr2	Return true if both expr1 and expr2 are true. Otherwise, returns false. If expr1 is false, returns false immediately without determining expr2.
or	3	expr1 or expr2	Return true if either expr1 or expr2 is true. Returns false if both expr1 and expr2 are false. If expr1 is true, returns true without determining expr2.
not	7	not expr	Return false if expr is true. Returns true if expr is false.

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3. Syntax