B.1  Variables, Data Types, Database Access, Declaring Variables, and Comments Watch Video ×

First and foremost, have fun when programming with sheerpower. It is fast. It is intuitive.

Variable names
User variable names must start with a letter and can include letters, numbers, the underscore ("_"), and an embedded dollar sign ("$"). Names are case-regardless. This means that Account is the same as AccOUNT. If a variable name consists of multiple words, by convention each word is separated by an underscore.

Primitive Data Types

• Real -- A number having up to 18 digits to the left of the decimal and 16 to the right. To support business applications, sheerpower uses Perfect Precision Math which eliminates rounding errors when performing simple math operations.
  
  When comparing two REAL values in sheerpower, the advantage lies in its Perfect Precision Math, which ensures exact arithmetic operations. This precision eliminates common floating-point errors seen in other languages, resulting in accurate comparisons. This is particularly beneficial for business applications where even minor discrepancies can have significant financial implications. The high precision and consistent results provided by sheerpower's REAL values make it a reliable choice for critical business computations.
• String -- Characters, such as a person's name, city name, and also arbitrary binary 8-bit data.
• Integer -- A whole number without fractional digits.
• Boolean -- A logical of true (1) or false (0). Used in conditional statements.
• Dynamic -- Can be any data type. Adjusts its data type according to use.
• Database access -- expressed by table_name(field_name)

Of these, the most commonly used data types are REAL, STRING, and BOOLEAN -- in that order. For business applications, INTEGER and DYNAMIC data types are less frequently used and rarely even needed. The default data type is REAL.

All database access in SheerPower is managed using the table_name(field_name) syntax. For example, the statement print payroll(salary) retrieves the current record from the payroll table, locks it if necessary, extracts the salary field, and prints its contents.

If you assign a value to a database field, as in payroll(salary) = 1234.56, SheerPower retrieves the current record from the payroll table, locks it, and stores the value 1234.56 into the salary field. The modified record will then be written back to the database and unlocked using a "lazy write" mechanism. This method ensures the integrity of the table by delaying the actual database write operation until it is most efficient.

SheerPower’s database access syntax is immune to SQL injection attacks because it avoids direct SQL manipulation by abstracting table access behind this syntax. For further details, visit the relevant section here.

Dynamic Adjustment of table_name(field_name)

In SheerPower, the treatment of table_name(field_name) is dynamic and adjusts based on the context in which it is used. This flexibility allows developers to handle different data types without the need for explicit conversions, simplifying code and reducing potential errors.

1. Numerical Context:

   When a field from a database table is used in a numerical context, such as in mathematical operations, SheerPower automatically interprets and converts the field's value to the appropriate numeric type. This makes it easy to perform calculations on database fields without requiring any manual type conversions.

   mysalary = 1.5 * payroll(salary)

   In this case, payroll(salary) retrieves the salary field from the payroll table. The value is automatically converted into a number, allowing it to be multiplied by 1.5 seamlessly. This dynamic conversion eliminates the need for explicit type management in mathematical operations.

2. String Context:

   When a field is used in a string context, SheerPower dynamically converts the value to a string. This is particularly useful when concatenating or formatting data from the database with other strings.

   mysalary$ = 'my ' + payroll(salary)

   Here, payroll(salary) retrieves the salary field from the payroll table, and the value is automatically treated as a string for concatenation with the text 'my '. The result, mysalary$, will hold the concatenated string without needing explicit conversion.

3. Advantages:
   • Seamless Type Handling: SheerPower dynamically adjusts the type of the database field based on its usage context, reducing the need for manual type conversion and simplifying the code.
   • Context-Aware Operations: Whether the field is used in mathematical calculations or string operations, SheerPower intelligently determines how to handle the field, ensuring that it behaves correctly in both contexts.
   • Efficient Database Interactions: The table_name(field_name) syntax provides a clean and efficient way to access and modify database fields, with built-in protections against SQL injection attacks, further enhancing security and performance.

This dynamic type conversion, coupled with the ease of use of table_name(field_name), allows developers to focus more on business logic rather than handling cumbersome type declarations or conversions.

Variables with a dollar sign "$" suffix default to being a string. Those with a percent sign "%" suffix default to being an integer. And those with a question mark "?" suffix default to being a boolean. Unsuffixed, undeclared variables are assumed to be declared as real.

Defining Constants
You can also define constants in your code. Constants cannot be accidently changed once defined. You can also require that all variables be declared. In this case, undeclared variables will cause compile-time errors.
Declaring Default Output Formatting
There are some variables that when printed you always want specific formatting to be used. For example, with a variable that contains cash, every time it is printed, you might want to include a dollar sign, commas, and also rounded to two decimal digits. For details on print formats, see the SPRINTF() function Custom Data Types
A custom data type is defined by: TYPE typename datatype [format 'format string']

After being defined, custom data types can be utilized in place of any primitive data type. If you declare a variable with a custom data type, any attempt to assign a different custom data type to that variable will generate a compile-time error. Custom data types also improve the readability of your code, making it easier to maintain in the long run. Comments in your code

Comments in your code should explain the reasoning behind specific logic. sheerpower ignores all comments since they are intended for your reference and for future developers who need to understand your code.

Comments are prefixed with either ! or //
! this is a comment
// this is a comment