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Programming Language Theory: Difference between revisions
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* Untagged variant records ("type punning") | * Untagged variant records ("type punning") | ||
* Procedure parameters | * Procedure parameters | ||
Static- vs dynamic-typing refers to (among other possible definitions) whether type is determined at compile-time or run-time. Among dynamic typing, ''duck typing'' types based on (dynamically-bound) method availability; variants of static typing include ''structural typing'' (relations based on form) and ''nominative typing'' (relations based on names). The benefits of static typing include: | Static- vs dynamic-typing refers to (among other possible definitions) whether type is determined at compile-time or run-time. Among dynamic typing, ''duck typing'' types based on (dynamically-bound) method availability; variants of static typing include ''structural typing'' (relations based on form) and ''nominative typing'' (relations based on names). Nominative typing has (predictable) problems with anonymous types, and also name shadowing. Structural typing has issues with recursive declarations, along with ambiguities regarding constituent ordering and nomenclature; it is used primarily in ML and research, with nominative typing dominating the mainstream. The benefits of static typing include: | ||
* Detection of many types of errors at compile-time | * Detection of many types of errors at compile-time | ||
** "Safety = Progress + Preservation" (Harper 1994) suggests well-typed expressions ought not get [[Programming_Language_Theory#Divergent_Combinators|stuck]], and that reductions of well-typed expressions are themselves well-typed. | ** "Safety = Progress + Preservation" (Harper 1994) suggests well-typed expressions ought not get [[Programming_Language_Theory#Divergent_Combinators|stuck]], and that reductions of well-typed expressions are themselves well-typed. | ||
