Merge branch 'AlexKnauth-and-let'

aand.rkt

@@ -0,0 +1,14 @@
+#lang racket/base
+
+(provide aand it)
+(require anaphoric/it
+         anaphoric/aif
+         syntax/parse/define
+         (for-syntax racket/base))
+
+(define-syntax aand
+  (syntax-parser
+    [(_) #'#true]
+    [(_ body:expr) #'body]
+    [(_ [variable:id condition:expr] rest ...+)
+     #'(aif condition (and-let rest ...) #false)]))

and-let.rkt

@@ -0,0 +1,15 @@
+#lang racket/base
+
+(provide and-let)
+
+(require syntax/parse/define
+         anaphoric/if-let
+         (for-syntax racket/base))
+
+(define-syntax and-let
+  (syntax-parser
+    [(_) #'#true]
+    [(_ body:expr) #'body]
+    [(_ [variable:id condition:expr] rest ...+)
+     #'(if-let [variable condition] (and-let rest ...) #false)]))
+

main.rkt

@@ -14,14 +14,18 @@
                        anaphoric/aif
                        anaphoric/awhen
                        anaphoric/acond
+                       anaphoric/aand
                        anaphoric/if-let
                        anaphoric/when-let
-                       anaphoric/cond-let))
+                       anaphoric/cond-let
+                       anaphoric/and-let))
 
 (require anaphoric/it
          anaphoric/aif
          anaphoric/awhen
          anaphoric/acond
+         anaphoric/aand
          anaphoric/if-let
          anaphoric/when-let
-         anaphoric/cond-let)
+         anaphoric/cond-let
+         anaphoric/and-let)

scribblings/anaphoric.scrbl

@@ -90,6 +90,24 @@ using @racket[it].
  at most once (evaluation stops at the first successful 
  @racket[conditionᵢ]).}
 
+@defform[(aand conditionᵢ ... body)]{
+ Variant of @racket[and] which binds @racket[it]
+ to the value of each @racket[conditionᵢ], in scope within the
+ next @racket[conditionᵢ] or @racket[body]. More precisely, the value
+ of each @racket[conditionᵢ] can be referred to as @racket[it] in
+ the following @racketvarfont{conditionᵢ₊₁}, and the value of the last
+ @racket[conditionᵢ] can be referred to as @racket[it] in the
+ @racket[body]. If there are no @racket[conditionᵢ], i.e. when
+ writing, @racket[(aand body)], then @racket[it] retains its original
+ binding (which means that @racket[it] could be unbound, e.g. if no
+ other @racketmodname[anaphoric] form wraps this one).
+
+ Each @racket[condition] is evaluated at most once, and
+ evaluation stops at the first false condition. The
+ @racket[body] is only evaluated when every
+ @racket[conditionᵢ] is successful.
+}
+
 @section{The hygienic versions @racket[if-let], 
  @racket[when-let] and @racket[cond-let]}
 
@@ -122,4 +140,16 @@ using @racket[it].
 
  Each @racket[conditionᵢ] is evaluated at most once
  (evaluation stops at the first successful 
- @racket[conditionᵢ]).}
+ @racket[conditionᵢ]).}
+
+@defform[(and-let [identifier conditionᵢ] ... body)]{
+ Variant of @racket[and] which binds each @racket[identifier]
+ to the value of its @racket[conditionᵢ], in scope within every
+ @racket[conditionᵢ] afterwards as well as in @racket[body].
+
+ Each @racket[conditionᵢ] is evaluated at most once, and
+ evaluation stops at the first false condition. The
+ @racket[body] is only evaluated when every
+ @racket[conditionᵢ] is successful.
+}
+