Language Evaluation Criteria PPL

Language Evaluation Criteria:
Some of the language criterias to evaluate a programming language are:

Readability
Writability
Reliability
Cost
Generality
Extensibility
Standardability
Support for internationalization

Readability: Coding should be simple and clear to understand.
1. Simplicity: Should not involve complex syntax, many ways to perform a single task,overloading of methods and operator etc.
2. Orthogonality: This means relatively small set of primitive constructs can be combine.
  - For ex., int *count; Here pointer and integer is combined.
  - Another ex., int count[ 5 ]; Here array and pointer is combine.
3. Control Statements: There should be adequate control statements.
  - Use of for loop, while loop, do while loop is adequate.
  - Using of go to statements causes poor readability.
4. Data Types and Structures: Language should involve adequate facilities for defining data types and data structure.
  - For ex., timeout = 1; is unclear as compare to timeout = true;.
5. Syntax Design: Syntax design affects the readability in the following way.
  1. Identifier forms: Restriction to very short length of identifier is a barrier to readability.
  2. Special words: Special words like while, for, class, int affects the readability of any language. If special words are allowed to be variable names than it will become confusing.
Writability: Writability is a measure of how easily language can be used to code.Most of the language characteristics that affect readability also affect writability.
1. Simplicity: Should not involve complex syntax, many ways to perform a single task,overloading of methods and operator etc.
2. Orthogonality: This means relatively small set of primitive constructs can be combine.
  - For ex., int *count; Here pointer and integer is combined.
  - Another ex., int count[ 5 ]; Here array and pointer is combine.
3. Support for Abstraction: Language should support process and data abstraction.
4. Expressivity: In less lines of code program should be writable.
  - For ex., for statements makes counting loops easier than while.
  - Another ex., is i++ is more expressive than i=i+1.
Reliability: A program is said to be reliable if it performs to irs specifications under all conditions.
1. Type Checking: It is testing for type error, either at compile or run time.
  - For ex., float percentage; is more desirable as compare to int percentage.
2. Exception Handling: It is the ability of program to handle run time error. Remember, handling runtime error are more expensive than compile errors.
3. Aliasing: It is same memory location (variable) having more than one name. Which is causes confusion.
4. Readability: Readability influences reliability.
5. Writability: Writability also influence reliability.
Cost: Total cost of programming should be minimum.
- For ex., cost of trainer.
- Cost of writing algorithm.
- Cost of compiling program in the language.
- Cost of hardware required for program.
- Cost of maintenance.
Generality: Language should not be limited to specific application only.
Extensibility: Should be flexible, must be able to add new constructs.
Standardability: Language should be platform independent.
Support for Internationalisation: Various formats like time, date, currency etc should be supportable.