A programming language is an artificial language that can control the behaviour of a machine, specifically in computers. Programming language like natural languages is defined by syntactic and semantic rules which define their structure and meaning respectively. The hierarchical structure of programming languages is as follows −Programs − Computer programs are instructions for a computer. A computer needed programs to function, generally executing the program’s instructions in the main processor. The program has an executable form that the computer can use directly to execute the instructions. The equivalent program in its human-readable source program form, from which executable programs are ... Read More

One-Pass CompilerOne pass compiler reads the code only once and then translates it. The one-pass compiler passes only once through the parts of each compilation unit. It can translate each part into its final machine program. In the one-pass compiler, when the line source is processed, it is scanned and the token is extracted. This is in contrast to a multi-pass compiler which modifies the program into one or more intermediate representations in steps between source program and machine program, and which convert the whole compilation unit in each sequential pass.A one-pass compiler is fast since all the compiler code ... Read More

The Chomsky hierarchy is a collection of various formal grammars. With the use of this formal grammar, it can generate some formal languages. They can be defined by multiple types of devices that can identify these languages such as finite state automata, pushdown automata, linear bounded automata, and Turing machines, respectively.Chomsky has suggested four different classes of phrase structure grammar as follows −Type-0 Grammar (Unrestricted Grammar) − Type-0 grammar is constructed with no restrictions on the replacement rule. A non-terminal must appear in the string on the left side. The language generated is called recursively enumerable language.Thus, type-0 grammar isAn ... Read More

The binding of a program element to a specific characteristic or property is the choice of the property from a set of possible properties. The time during program organization or processing when this choice is made is defined as the binding time of that property for that element. There are multiple varieties of bindings in programming languages, and a variety of binding times. It can also involve within the terms of binding and binding time the properties of program elements that are constant either by the definition of the language or its execution.Types of Binding TimesThere are two types of ... Read More

Programming environments have affected language design generally in two major areas such as features promoting separate compilation and assembly of a program from components, and features aiding program testing and debugging.Separate compilation − In the structure of any huge program it is regularly desirable to have multiple programmers or programming group design, code, and test elements of the program before the last assembly of all the elements into a complete program. This needed the language to be structured so that single subprograms or other elements can be separately compiled and implemented, without the other element, and thus later combined without ... Read More

The type conversion is an operation that takes a data object of one type and creates the equivalent data objects of multiple types. The signature of a type conversion operation is given as                   conversion_op :type1→type2There are two types of type conversions which are as follows −Implicit type conversion (Coercions) − The programming languages that enable mixed-mode expressions should describe conventions for implicit operand type conversions.Coercion is defined as an automatic conversion between types. For example in Pascal, if the operands for the addition operation are of integer type and other real types, ... Read More

Type checking is the activity of providing that the operands of an operator are of compatible types. A compatible type is one that is legal for the operator or is enabled under language rules to be implicitly modified by compiler-generated code to a legal type. This automatic conversion is known as coercion. A type error is the application of an operator to an operand of an improper type. It can illustrate the concept of type checking considers the following statement.c:=a + 3 * b;Here b should be of a type that allows multiplication by an integer. Similarly, the operands for ... Read More

DefinitionIt recognizes the code or data related to the name of the variable, function, class, etc. The definition is essentially needed by the compiler to designate the storage area for the declared entity. When a variable is defined it has an amount of memory that includes multiple bytes for that variable.A function definition generates code for the function. It can define a program element only once in a program because the definition is a unique requirement of a program element. The relationship between declaration and definition can be one-to-many.DeclarationIt can determine the names of the program including the name of ... Read More

The whole source program can be processed several times before generating the assembly/machine code.Pass − One complete scan or processing of the source program. Various phases can be arranged into one pass. Lexical, syntax & semantic analysis are often grouped in a single pass. Each pass reads the source program and writes output into an intermediate file, which then can be read by subsequent passes, i.e., the output of one pass will be input to the next pass.Single-Pass Compiler − In a single-pass compiler, when a line source is processed it is scanned and the tokens are extracted. Then the ... Read More

Solution                    Symbol TableS.NO.Variable NameVariable Type200AFloat204BFloat208CFloatNow, we will see how we can perform the compiler phase at each level and how it works.Lexical AnalysisThis is the first step that works as an integration between the compiler and the source language code. It reads the source code one character at a time and designs a source code into a series of atomic units known as tokens.In this phase, we will see how we can tokenize the expression.A → Identifier: (id, 1)= → Operator: AssignmentB → Identifier: (id, 2)* → Operator: MultiplicationC → Identifier: ... Read More