What is denotational semantics used for?
In computer science, denotational semantics is an approach for providing mathematical meaning to systems and programming languages. In other words, denotational semantics is a formal technique for expressing the semantic definition of a programming language.
What is the difference between denotational and axiomatic semantics?
operational: related to the activities involved in doing or producing something. denotational: the main meaning of a word. axiomatic: obviously true and therefore not needing to be proved.
What is an assertion in axiomatic semantics?
Axiomatic semantics define the meaning of a command in a program by describing its effect on assertions about the program state. The assertions are logical statements—predicates with variables, where the variables define the state of the program.
What is operational language?
Operational semantics is a category of formal programming language semantics in which certain desired properties of a program, such as correctness, safety or security, are verified by constructing proofs from logical statements about its execution and procedures, rather than by attaching mathematical meanings to its …
What is denotational theory of meaning?
a. The referential or denotational theory: The meaning of an expression is what it refers to or denotes. This theory of meaning emphasizes the relationship between language and objects. The ability of an individual word to specify an object is best seen in proper names, because the given name specifies only one thing.
What is the difference between operational and denotational semantics?
But usually there is a distinct gap between operational and denotational semantics: The operational semantics is the specification of an interpreter for the programming language whereas the denotational semantics tries to capture the mathematically essence of a program, abstracting away from computational details.
What is the difference between static and dynamic semantics?
Static objects are constructs (identifiers, statements, expressions etc.) in the text of the program, and have no meaningful existence beyond compile-time. Dynamic objects are (instances of) values, locations and the like, which live and move and have their being inside the computer at run-time.
What does axium mean?
An axiom is a statement that everyone believes is true, such as “the only constant is change.” Mathematicians use the word axiom to refer to an established proof. The word axiom comes from a Greek word meaning “worthy.” An axiom is a worthy, established fact.
When would you use operational semantics?
An operational semantics for a programming language is a means for understanding in precise detail the meaning of an expression in the language. It is the formal specification of the language that is used when writing compilers and interpreters, and it allows us to rigorously verify things about the language.
What are the goals of semantic theory?
The goal of semantic theory is to build a theory that can explain why we have these intuitions. Like any theory, it will be based on the basic data of the theory – semantic intuitions.
What is semantics in C programming?
Semantics describes the processes a computer follows when executing a program in that specific language. This can be shown by describing the relationship between the input and output of a program, or an explanation of how the program will be executed on a certain platform, hence creating a model of computation.
What is denotational semantics?
Denotational semantics is ascribed to a program phrase as a function from an environment (holding the current values of its free variables) to its denotation. For example, the phrase n*m produces a denotation when provided with an environment that has binding for its two free variables: n and m.
What are the semantics of a non-trivial language?
For a non-trivial language, an English description is almost sure to be ambiguous, or to have some details omitted. This means giving a compiler or interpreter for the language. The semantics of the language are implicitly defined by the behavior of the compiled/interpreted code.
How do you define the semantics of a language?
The semantics of the language are implicitly defined by the behavior of the compiled/interpreted code. The problem is that it provides little help with reasoning about programs, and does not a provide an input language for a tool generator. This involves giving an axiom or a rule of inference for each construct in the language.
What is a semantic domain?
A semantic domain can be primitive (i.e., we already understand it, like the domain of natural numbers) or compound (built from existing domains using operators like x, →, etc). Valuation functions: One function is defined for each “syntactic domain”; i.e., one function for each nonterminal in the grammar.