Clear the Macro Symbol Table

The symclear function clears the macro symbol table of any stored macro variables and macro functions. The function is used to avoid contamination between one call to msource and the next. It is called automatically when the "clear" parameter of msource is set to TRUE. If the "clear" parameter is set to FALSE, you can clear the symbol table manually with the symclear function.

symclear(variables = TRUE, functions = TRUE)

Arguments

variables

Whether or not to clear the macro symbol table. Default is TRUE.

functions

Whether or not to clear the macro function list. Default is TRUE.

Value

The number of objects cleared, invisibly. The function also outputs a message saying how many objects were cleared.

See also

msource()

Other symtable: print.symtable(), symget(), symput(), symtable()

Examples

library(macro)

# Get path to demo macro program
src <- system.file("extdata/Demo4.R", package = "macro")

# Display source code
# - This is the macro input code
cd <- readLines(src)
cat(paste(cd, "\n"))
# #% Create some macro variables
# #%let x <- 1
# #%let y <- 2
# #%let z <- &x + &y
#
# #% Create a macro function
# #%macro test(vl = Hello!)
# print("&vl")
# #%mend

# Execute source code
msource(src, echo = FALSE)

# View symbol table
symtable()
# # Macro Symbol Table: 3 macro variables
#   Name Value
# 1   &x     1
# 2   &y     2
# 3   &z 1 + 2
# # Macro Function List: 1 macro functions
#   Name Parameter Default
# 1 test        vl  Hello!

# Clear symbol table
symclear()
# Clearing macro symbol table...
# 4 items cleared.

# View symbol table again
symtable()
# # Macro Symbol Table: (empty)
# # Macro Function List: (empty)