VTLUUG:2016-03-24

Our seventh meeting of the 2016 Spring semester, and Officer Elections

Date, Time, and Location

• Thursday, 24 March
• 8:30pm - 10:30pm
• 1040 Torgersen Hall

Announcements

• #VTLUUG: "No Rules, Just Right™"
• 2016 is the year of the Linux desktop
• For shell account, contact uncurlhalo
• Interest gauge for SouthEast LinuxFest 2016

Curriculum du jour

• Officer Elections
  • This is a consequence of new club registration policies.

Results

• President
  • Jacob Melton
• VP of not IT
  • Marcus Wanners
• Secretary/Treasurer
  • John Volk

Talks

• ackthet is giving the talk: Lambda Calculus for Babies. Retarded Babies.
  • First in ackthet's 10-part talk on Xmonad, starting from the basics of haskell

Hacking

• Gobblerpedia
• VTLUUG Wiki
• Wiki meeting page creation script -- this needs to happen so echarlie isn't doing it manually
• New Website?
• Infrastructure 2016

Lambda Calculus for Babies: Retarded Babies

Lambda Calculus forms the fundamentals of functional programming. If it can be described as a function, it can be described in the lambda calculus and consequently written in Haskell

Slides

Alpha equivalence

• Variable name doesn't matter

Beta reduction

Meat of Lambda calculus.

Currying

Allows for nested functions. Functions manipulate each input individually

Examples

 
(ƛx.x)2
(ƛ[x:=2])        x is bound to 2
 2

                    

(ƛz.zz)(ƛy.yy)
(ƛ[z:=(ƛy.yy)].zz)
(ƛy.yy)(ƛy.yy)
(ƛy.yy)
 1

Currying example:

(ƛabc.cba)zz(ƛwv.w)
(ƛa.(ƛb.(ƛc.cba)))(z)z(ƛw.(ƛv.w)))   The first function only applies the first z
(ƛb.(ƛc.cbz))z(ƛw.(ƛv.w))            Applies from the outer parenthesis in
(ƛc.czz)(ƛw.(ƛv.w))                  So c is applied last
(ƛw.(ƛv.w))zz
(ƛv.z)z
 z

(ƛx.ƛy.xyy)(ƛa.a)b
(ƛy.(ƛa.a)yy)(b)
(ƛa.a)bb
 bb

(ƛx.x)(ƛy.yy)(ƛz.zq)    (ƛx.x) is the identity
(ƛy.yy)(ƛz.zq)
(ƛz.zq)(ƛz.zq)
 qq