[e-lang] Left-to-right define syntax: "into"

[Kevin Reid]

This is the current idea for left-to-right define syntax which Mark  
Miller and I have been discussing:

   VALUE into PATTERN
   VALUE into ^(EJECTOR) PATTERN

It is left-associative and its precedence is immediately above  
sequences; that is, it parses like this (actual test cases from E-on- 
CL):

? t("a; def b := c into d; e")
# stdout: SeqE. []
#           NounE. a
#           IntoE.
#             DefrecE.
#               FinalP.
#                 NounE. b
#                 null
#               NounE. c
#               null
#             null
#             FinalP.
#               NounE. d
#               null
#           NounE. e

? t("a into b into c")
# stdout: IntoE.
#           IntoE.
#             NounE. a
#             null
#             FinalP.
#               NounE. b
#               null
#           null
#           FinalP.
#             NounE. c
#             null



This is the portion of the grammar which implements it; "withinInto"  
is the next precedence level.


eExpr:      withinInto
             ("into"^ {##.setType(IntoExpr);} intoOptEjector pattern)* ;

intoOptEjector: "^"! parenExpr | filler ;
withinInto:     assign | ejector ;

-- 
Kevin Reid                            <http://homepage.mac.com/kpreid/>