r - 当目标函数有默认值时，如何编写一个可以遵循默认值的包装函数？

Answer 1

I'll reply myself with even more elaborate setup (I replaced targetf with lib* names). The bar functions are nested inside foo ones, so their default values are not easily visible to the user.

libfoo<-function(par1=1,...)
{
    if (missing(par1))
    {
        warning("par1 is missing!!")
    }
    print(paste0('par1: ',par1))
    libbar(...)
}


libbar<-function(par2=1)
{
    if (missing(par2))
    {
        warning("par2 is missing!!")
    }
    print(paste0('par2: ',par2))
}


libfoo2<-function(par3=1,...)
{
    if (missing(par3))
    {
        warning("par3 is missing!!")
    }
    print(paste0('par3: ',par3))
    libbar2(...)
}

libbar2<-function(par4=1)
{
    if (missing(par4))
    {
        warning("par4 is missing!!")
    }
    print(paste0('par4: ',par4))
}

The wrapper:

wrapfun<-function(x,par1=3,...,par3,par4)
{
    libfoo(par1,...) #With dots everything is simple

    pars<-list()
    if(!missing(par3))
    {
        pars<-c(pars,par3=par3)
    }
    if(!missing(par4))
    {
        pars<-c(pars,par4=par4)
    }
    do.call(libfoo2,pars) #This is how we can pass specific arguments, and respecting missings properly.
}

This is some output:

wrapfun(par1=5,par2=5,par3=5,par4=5)
# [1] "par1: 5"
# [1] "par2: 5"
# [1] "par3: 5"
# [1] "par4: 5"


wrapfun()
# [1] "par1: 3"
# [1] "par2: 1"
# [1] "par3: 1"
# [1] "par4: 1"
# Warning messages:
# 1: In libbar(...) : par2 is missing!!
# 2: In (function (par3 = 1, ...)  : par3 is missing!!
# 3: In libbar2(...) : par4 is missing!!

wrapfun(par4=5)
# [1] "par1: 3"
# [1] "par2: 1"
# [1] "par3: 1"
# [1] "par4: 5"
# Warning messages:
# 1: In libbar(...) : par2 is missing!!
# 2: In (function (par3 = 1, ...)  : par3 is missing!!