Allow variants to be spread across multiple parsing words with a VARIANT-MEMBER:...

[factor.git] / extra / variants / variants-docs.factor

diff --git a/extra/variants/variants-docs.factor b/extra/variants/variants-docs.factor
index 9a230a85352b39f92e75a086283abc3a35f4d532..e23b3ee8941256a2b8a2417df94c31605533e71c 100644 (file)
--- a/extra/variants/variants-docs.factor
+++ b/extra/variants/variants-docs.factor
@@ -13,7 +13,7 @@ VARIANT: class-name
     .
     .
     ; """ }
-{ $description "Defines " { $snippet "class-name" } " as a union of the following " { $link singleton-class } " and " { $link tuple-class } " definitions. Each " { $snippet "singleton" } " word is defined as a " { $snippet "singleton-class" } ", and each " { $snippet "tuple" } " word is defined aas a " { $snippet "tuple-class" } " with the given set of " { $snippet "slot" } "s, using the same syntax for slot specifiers as " { $link POSTPONE: TUPLE: } ". Typed tuple slots can recursively reference the variant " { $snippet "class-name" } " being defined. For " { $snippet "tuple" } " types, a " { $link boa } " constructor word " { $snippet "<tuple>" } " is defined as well." }
+{ $description "Defines " { $snippet "class-name" } " as a union of the following " { $link singleton-class } " and " { $link tuple-class } " definitions. Each " { $snippet "singleton" } " word is defined as a " { $snippet "singleton-class" } ", and each " { $snippet "tuple" } " word is defined as a " { $snippet "tuple-class" } " with the given set of " { $snippet "slot" } "s, using the same syntax for slot specifiers as " { $link POSTPONE: TUPLE: } ". Typed tuple slots can recursively reference the variant " { $snippet "class-name" } " being defined. For " { $snippet "tuple" } " types, a " { $link boa } " constructor word " { $snippet "<tuple>" } " is defined as well." }
 { $examples { $code """
 USING: kernel variants ;
 IN: scratchpad
@@ -24,6 +24,18 @@ VARIANT: list
     ;
 """ } } ;
 
+HELP: VARIANT-MEMBER:
+{ $description "Defines a new member of a variant class without restricting such definitions to a single statement or source file. The variant class should be listed first, and the class member should follow." }
+{ $examples { $code """
+USING: kernel variants ;
+IN: scratchpad
+
+VARIANT: list ;
+
+VARIANT-MEMBER: list nil
+VARIANT-MEMBER: list cons: { { first object } { rest list } }
+""" } } ;
+
 HELP: match
 { $values { "branches" array } }
 { $description "Dispatches on the type of the value on the top of the stack. If the type is a " { $link singleton-class } ", the corresponding quotation is called with the underlying stack unchanged. If the type is a " { $link tuple-class } ", the tuple slots are pushed onto the stack by order of arguments." }
@@ -58,6 +70,7 @@ ARTICLE: "variants" "Algebraic data types"
 "The " { $vocab-link "variants" } " vocabulary provides syntax and combinators for defining and manipulating algebraic data types."
 { $subsections
     POSTPONE: VARIANT:
+    POSTPONE: VARIANT-MEMBER:
     variant-class
     match
 } ;