listcompr 0.4.0

renamed expr and str to .expr and .str in all the gen.... functions to allow variables like s and e (fixes https://github.com/patrickroocks/listcompr/issues/7)
allow (x_1, ..., x_n) short-cuts in nested expressions
allow a_i placeholders within nested vector and list expressions
improved warnings/error messages
fixed infinite recursion occurring when a NULL variable range was given
fix auto-generated column names in a data frame for c(a, c)

listcompr 0.3.0

modified internal conversion from lists to data frames in gen.data.frame such that non-fundamental types are accepted (fixes https://github.com/patrickroocks/listcompr/issues/5)
added a check to ensure that the inner expression for gen.(named).(data.frame|matrix) must be exactly one row
some output format fixes (data frames and matrices where sometimes mixed up)
added byrow parameter to gen.(named).(data.frame|matrix) which applies the Cartesian product by column to the expression
fixed that gen.named.(vector|list) can be used as an inner expression of other gen.-functions
gen.list and similar functions accept characters with placeholders, removed gen.list.char and gen.vector.char
changed order of dimensions in gen.matrix for auto-detected 2-dim matrix
gen.matrix automatically searches for two dimensions in the … arguments
fixed missing column names in gen.named.data.frame
added gen.matrix and gen.named.matrix for generating (named) matrices

variable ranges can also be of character type (fixes https://github.com/patrickroocks/listcompr/issues/1)
fixed sorting of free variables (fixes https://github.com/patrickroocks/listcompr/issues/2)
auto-detect column names when generating data frames where a symbol is in the base expression
fixed missing export of gen.logical.or, added example to the vignette
allow substitutions in the list comprehension arguments