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Pattern
Grammar


 

The Such-That Pattern (non associative)

Grammar Meaning Expansion
pattern "?" prefixExpr
If the match succeeds and expr is true
kernel

 

The List Patterns (right associative)

Grammar Meaning Expansion
"[" patt0,... "]" + pattn
match respective elements, and the rest
kernel
"[" patt0,... "]"
match exactly the respective elements
[patt0,...] + ==[]

 

The Exact-Match Pattern (non-associative)

Grammar Meaning Expansion
"==" primExpr
If the match succeeds and expr is true
t ? (t == primExpr)

 

The Quasi-Literal Patterns (non associative)

Grammar Meaning Expansion
parserName`quasi`

Almost literal pattern in an embedded grammar

t ? (quasiParsers["parserName"] \
      matchMaker("quasiString") \
      matchBind([arg,..], t) \
      =~ [patt,...])
`quasi`

Defaults to the "simple" quasi-parser

simple`quasi`

 

The Namer Pattern (non associative)

Grammar Meaning Expansion
varName ":" primExpr

Bind the name to a constructed slot

kernel
varName

no explicit SlotMaker

either
    varName :final
or
    varName :settable
"&" varName

Bind the slot rather than the value

varName : defineSlot
"_"

Matches everything, binds nothing

kernel

 

 

 

 
Unless stated otherwise, all text on this page which is either unattributed or by Mark S. Miller is hereby placed in the public domain.
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