Mark a file as input to the script. This function simply returns the path and is used for static analysis to determine script dependencies. It can be used directly when reading files.
Examples
# In a bakepipe script, mark a file as input and use it directly when reading
# data <- read.csv(file_in("processed.csv"))
# The function simply returns the path unchanged
file_path <- file_in("data.csv")
print(file_path) # "data.csv"
#> [1] "data.csv"