f# - Why is using the base key word causing this error? -

i trying example programming f# o'railey, chris smith page 53.

it working functions returning functions.

this line straight book in vs2013 ide editor, fsi , linqpad4 giving error:

code:

let generatepoweroffunc base = (fun exponent -> base ** exponent) 

error:

error fs0010: unexpected keyword 'base' in pattern 

what missing or there author did not include needs included.

i suspect it's merely matter of base not being keyword when book written.

try different identifier:

let generatepoweroffunc b = (fun exponent -> b ** exponent) 

assuming you've got 2009 edition of programming f#, before f# 2.0 released (although after 1.0). i'm trying find out when introduced keyword...

edit: actually, looking @ this version of spec written in 2009, looks base keyword @ point. wonder whether original code written before book published.

either way, think it's reasonable treat error, , using valid identifier instead should fine.

edit: it's listed in book's errata:

example 3-3 not work as-is in vs 2010. "base" apparently keyword, should have been escaped or there voodoo make not keyword i've missed in book. line 2 of example should this:

   let generatepoweroffunc ``base`` = (fun exponent -> ``base`` ** exponent);; 

alternatively, different variable name should chosen.

note author or editor:
feedback, must have missed keyword being marked reserved late in product cycle.

in future version of book i'll have read:

 let generatepoweroffunc basevalue = (fun exponent -> basevalue ** exponent);;