Print free objects

Print methods for free objects

Usage

# S3 method for class 'free'
print(x,...)
as.character_free(m,latex=getOption("latex"))

Arguments

x

Object of class free in the print method

m

A two-row matrix in function as.character_free()

latex

Boolean, with TRUE meaning to print latex-friendly output including curly braces, and default NULL option meaning to give a nicer-looking output that latex would typeset incorrectly

...

Further arguments, currently ignored

Author

Robin K. S. Hankin

Note

The print method does not change the internal representation of a free object, which is a list of integer matrices.

The default print method uses multiplicative notation (powers) which is inconsistent with the juxtaposition method “+”.

The print method has special dispensation for length-zero free objects but these are not handled entirely consistently.

The default print method uses lowercase letters a-z, but it is possible to override this using options("freegroup_symbols" = foo), where foo is a character vector. This is desirable if you have more than 26 symbols, because unallocated symbols appear as NA.

The package will allow the user to set options("freegroup_symbols") to unhelpful things like rep("a",20) without complaining (but don't actually do it, you crazy fool).

See also

char_to_free

Examples

## default symbols:

abc(26)
#> [1] a.b.c.d.e.f.g.h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z
rfree(1,10)
#> [1] i^7.g^6.i^9.h^4.b^2.c^-8.g^10.j^7.e^6.j^9


# if we need more than 26:
options(freegroup_symbols=state.name)
rfree(10,4)
#>  [1] Alabama.Alaska^4.Arkansas^-2.Arizona       
#>  [2] Alabama^3.Arkansas^2                       
#>  [3] Arkansas^-4.Arizona^-2                     
#>  [4] Arizona^-4                                 
#>  [5] Arkansas^-2.Arizona^2.Alabama^-1           
#>  [6] Alabama^2.Alaska^2.Arkansas^3              
#>  [7] Alabama^-4.Arizona^4.Alabama^-2.Alaska^-3  
#>  [8] Arizona^2.Alaska^-3.Arkansas               
#>  [9] Arkansas^4.Alaska^-3.Arizona^-4.Arkansas^-1
#> [10] Arizona^4.Alabama^-2                       

# or even:
jj <- letters[1:10]
options(freegroup_symbols=apply(expand.grid(jj,jj),1,paste,collapse=""))
rfree(10,10,100,4)
#>  [1] ji^2.bd.dj.ge^2.dc^4.jb^4.bc^4.bg^4.eh^3.hi^3  
#>  [2] jd^4.cg^2.hj^3.ca.ag^2.ji^4.ai^2.fa^3.ie^4.jb^4
#>  [3] fi^5.cj^3.fj^2.ha^2.dg^4.de^3.cb^4.jc^4.ei^4   
#>  [4] cg.gc^3.fi^4.if.ed.eg^3.bg^3.gg.ii^2.bb        
#>  [5] cc^2.cf.dg^3.cj.fd^2.ga^3.jj.bh.dg^3.dc        
#>  [6] jc^3.hg^3.db^3.aj^3.ed^4.jc^3.gf.bi^4.ag^4.ib  
#>  [7] eb^4.ba.ha^4.ab^2.gj.bb^2.fi^2.ah^2.ia^2.cg^3  
#>  [8] bg^4.hi^2.ig^2.cb^2.hh^4.ah^3.jd.gg^2.ef^5     
#>  [9] eh^2.hc^2.hj^3.jf.fd^3.de.ih^3.ii^4.df.ec      
#> [10] je^4.ji.hc^4.eb.ia^4.ee^4.fh^3.hb^3.hh^2.jg^4  

options(freegroup_symbols=NULL)  #  NULL is interpreted as letters a-z
rfree(10,4)            #  back to normal
#>  [1] b^-4.a^4.c^4.a^3 b^-4.c^4         c.d^-3.c^-1      d^-2.b^2        
#>  [5] b.a^-1           d^2.b^-4         d^3.c^-1.d       d^-1.c^-1.d     
#>  [9] c^9.b^2          c^-4.b^4.c^-1