How do I avoid eval and parse?












10















I have written a function that sources files that contain scripts for other functions and stores these functions in an alternative environment so that they aren't cluttering up the global environment. The code works, but contains two instances of eval(parse(...)):



# sourceFunctionHidden ---------------------------
# source a function and hide the function from the global environment
sourceFunctionHidden <- function(functions, environment = "env", ...) {
if (environment %in% search()) {
while (environment %in% search()) {
if (!exists("counter", inherits = F)) counter <- 0
eval(parse(text = paste0("detach(", environment, ")")))
counter <- counter + 1
}
cat("detached", counter, environment, "sn")
} else {cat("no", environment, "attachedn")}
if (!environment %in% ls(.GlobalEnv, all.names = T)) {
assign(environment, new.env(), pos = .GlobalEnv)
cat("created", environment, "n")
} else {cat(environment, "already existsn")}
sapply(functions, function(func) {
# source(paste0("C:/Users/JT/R/Functions/", func, ".R"), .env)
source(paste0("C:/Users/JT/R/Functions/", func, ".R"))
eval(parse(text = paste0(environment, "$", func," <- ", func)))
cat(func, "created in", environment, "n")
})
# rm(list = functions, pos = .GlobalEnv)
eval(parse(text = paste0("attach(", environment, ")")))
cat("attached", environment, "nn")
}


Much has been written about the sub-optimality of the eval(parse(...)) construction (see here and here). However, the discussions that I've found mostly deal with alternate strategies for subsetting. The first instance of eval(parse(...)) in my code doesn't involve subsetting (the second instance might be related to subsetting).



Is there a way to call new.env(...) and [environment name]$[function name] <- [function name] without resorting to eval(parse(...))? Thanks.



N.B.: I don't want to change the names of my functions to .name to hide them in the global environment










share|improve this question























  • Just discovered that eval(parse(text = paste0("detach(", environment, ")"))) can be replaced with detach(environment, character.only = T). The question about improving eval(parse(text = paste0("attach(", environment, ")"))) remains.

    – Josh
    15 mins ago


















10















I have written a function that sources files that contain scripts for other functions and stores these functions in an alternative environment so that they aren't cluttering up the global environment. The code works, but contains two instances of eval(parse(...)):



# sourceFunctionHidden ---------------------------
# source a function and hide the function from the global environment
sourceFunctionHidden <- function(functions, environment = "env", ...) {
if (environment %in% search()) {
while (environment %in% search()) {
if (!exists("counter", inherits = F)) counter <- 0
eval(parse(text = paste0("detach(", environment, ")")))
counter <- counter + 1
}
cat("detached", counter, environment, "sn")
} else {cat("no", environment, "attachedn")}
if (!environment %in% ls(.GlobalEnv, all.names = T)) {
assign(environment, new.env(), pos = .GlobalEnv)
cat("created", environment, "n")
} else {cat(environment, "already existsn")}
sapply(functions, function(func) {
# source(paste0("C:/Users/JT/R/Functions/", func, ".R"), .env)
source(paste0("C:/Users/JT/R/Functions/", func, ".R"))
eval(parse(text = paste0(environment, "$", func," <- ", func)))
cat(func, "created in", environment, "n")
})
# rm(list = functions, pos = .GlobalEnv)
eval(parse(text = paste0("attach(", environment, ")")))
cat("attached", environment, "nn")
}


Much has been written about the sub-optimality of the eval(parse(...)) construction (see here and here). However, the discussions that I've found mostly deal with alternate strategies for subsetting. The first instance of eval(parse(...)) in my code doesn't involve subsetting (the second instance might be related to subsetting).



Is there a way to call new.env(...) and [environment name]$[function name] <- [function name] without resorting to eval(parse(...))? Thanks.



N.B.: I don't want to change the names of my functions to .name to hide them in the global environment










share|improve this question























  • Just discovered that eval(parse(text = paste0("detach(", environment, ")"))) can be replaced with detach(environment, character.only = T). The question about improving eval(parse(text = paste0("attach(", environment, ")"))) remains.

    – Josh
    15 mins ago
















10












10








10








I have written a function that sources files that contain scripts for other functions and stores these functions in an alternative environment so that they aren't cluttering up the global environment. The code works, but contains two instances of eval(parse(...)):



# sourceFunctionHidden ---------------------------
# source a function and hide the function from the global environment
sourceFunctionHidden <- function(functions, environment = "env", ...) {
if (environment %in% search()) {
while (environment %in% search()) {
if (!exists("counter", inherits = F)) counter <- 0
eval(parse(text = paste0("detach(", environment, ")")))
counter <- counter + 1
}
cat("detached", counter, environment, "sn")
} else {cat("no", environment, "attachedn")}
if (!environment %in% ls(.GlobalEnv, all.names = T)) {
assign(environment, new.env(), pos = .GlobalEnv)
cat("created", environment, "n")
} else {cat(environment, "already existsn")}
sapply(functions, function(func) {
# source(paste0("C:/Users/JT/R/Functions/", func, ".R"), .env)
source(paste0("C:/Users/JT/R/Functions/", func, ".R"))
eval(parse(text = paste0(environment, "$", func," <- ", func)))
cat(func, "created in", environment, "n")
})
# rm(list = functions, pos = .GlobalEnv)
eval(parse(text = paste0("attach(", environment, ")")))
cat("attached", environment, "nn")
}


Much has been written about the sub-optimality of the eval(parse(...)) construction (see here and here). However, the discussions that I've found mostly deal with alternate strategies for subsetting. The first instance of eval(parse(...)) in my code doesn't involve subsetting (the second instance might be related to subsetting).



Is there a way to call new.env(...) and [environment name]$[function name] <- [function name] without resorting to eval(parse(...))? Thanks.



N.B.: I don't want to change the names of my functions to .name to hide them in the global environment










share|improve this question














I have written a function that sources files that contain scripts for other functions and stores these functions in an alternative environment so that they aren't cluttering up the global environment. The code works, but contains two instances of eval(parse(...)):



# sourceFunctionHidden ---------------------------
# source a function and hide the function from the global environment
sourceFunctionHidden <- function(functions, environment = "env", ...) {
if (environment %in% search()) {
while (environment %in% search()) {
if (!exists("counter", inherits = F)) counter <- 0
eval(parse(text = paste0("detach(", environment, ")")))
counter <- counter + 1
}
cat("detached", counter, environment, "sn")
} else {cat("no", environment, "attachedn")}
if (!environment %in% ls(.GlobalEnv, all.names = T)) {
assign(environment, new.env(), pos = .GlobalEnv)
cat("created", environment, "n")
} else {cat(environment, "already existsn")}
sapply(functions, function(func) {
# source(paste0("C:/Users/JT/R/Functions/", func, ".R"), .env)
source(paste0("C:/Users/JT/R/Functions/", func, ".R"))
eval(parse(text = paste0(environment, "$", func," <- ", func)))
cat(func, "created in", environment, "n")
})
# rm(list = functions, pos = .GlobalEnv)
eval(parse(text = paste0("attach(", environment, ")")))
cat("attached", environment, "nn")
}


Much has been written about the sub-optimality of the eval(parse(...)) construction (see here and here). However, the discussions that I've found mostly deal with alternate strategies for subsetting. The first instance of eval(parse(...)) in my code doesn't involve subsetting (the second instance might be related to subsetting).



Is there a way to call new.env(...) and [environment name]$[function name] <- [function name] without resorting to eval(parse(...))? Thanks.



N.B.: I don't want to change the names of my functions to .name to hide them in the global environment







r eval






share|improve this question













share|improve this question











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share|improve this question










asked 4 hours ago









JoshJosh

19512




19512













  • Just discovered that eval(parse(text = paste0("detach(", environment, ")"))) can be replaced with detach(environment, character.only = T). The question about improving eval(parse(text = paste0("attach(", environment, ")"))) remains.

    – Josh
    15 mins ago





















  • Just discovered that eval(parse(text = paste0("detach(", environment, ")"))) can be replaced with detach(environment, character.only = T). The question about improving eval(parse(text = paste0("attach(", environment, ")"))) remains.

    – Josh
    15 mins ago



















Just discovered that eval(parse(text = paste0("detach(", environment, ")"))) can be replaced with detach(environment, character.only = T). The question about improving eval(parse(text = paste0("attach(", environment, ")"))) remains.

– Josh
15 mins ago







Just discovered that eval(parse(text = paste0("detach(", environment, ")"))) can be replaced with detach(environment, character.only = T). The question about improving eval(parse(text = paste0("attach(", environment, ")"))) remains.

– Josh
15 mins ago














2 Answers
2






active

oldest

votes


















3














If you want to keep it off global_env, put it into a package. It's common for people in the R community to put a bunch of frequently used helper functions into their own personal package.






share|improve this answer
























  • I agree. I eventually need to learn how to do this.

    – Josh
    14 mins ago



















3














For what its worth, the function source actually uses eval(parse(...)), albeit in a somewhat subtle way. First, .Internal(parse(...)) is used to create expressions, which after more processing are later passed to eval. So eval(parse(...)) seems to be good enough for the R core team in this instance.



That said, you don't need to jump through hoops to source functions into a new environment. source provides an argument local that can be used for precisely this.




local: TRUE, FALSE or an environment, determining where the parsed expressions are evaluated.




An example:



env = new.env()
source('test.r', local = env)


testing it works:



env$test('hello', 'world')
# [1] "hello world"
ls(pattern = 'test')
# character(0)


And an example test.r file to use this on:



test = function(a,b) paste(a,b)





share|improve this answer
























  • Thank you, I missed that aspect of source(). However, if I change that line of code to source(paste0("C:/Users/JT/R/Functions/", func, ".R"), local = environment) I get the error Error in source(paste0("C:/Users/JT/R/Functions/", func, ".R"), local = environment) : 'local' must be TRUE, FALSE or an environment. Is there a way to convert the "env" that comes from environment to env?

    – Josh
    6 mins ago














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2 Answers
2






active

oldest

votes








2 Answers
2






active

oldest

votes









active

oldest

votes






active

oldest

votes









3














If you want to keep it off global_env, put it into a package. It's common for people in the R community to put a bunch of frequently used helper functions into their own personal package.






share|improve this answer
























  • I agree. I eventually need to learn how to do this.

    – Josh
    14 mins ago
















3














If you want to keep it off global_env, put it into a package. It's common for people in the R community to put a bunch of frequently used helper functions into their own personal package.






share|improve this answer
























  • I agree. I eventually need to learn how to do this.

    – Josh
    14 mins ago














3












3








3







If you want to keep it off global_env, put it into a package. It's common for people in the R community to put a bunch of frequently used helper functions into their own personal package.






share|improve this answer













If you want to keep it off global_env, put it into a package. It's common for people in the R community to put a bunch of frequently used helper functions into their own personal package.







share|improve this answer












share|improve this answer



share|improve this answer










answered 3 hours ago









thcthc

5,37611224




5,37611224













  • I agree. I eventually need to learn how to do this.

    – Josh
    14 mins ago



















  • I agree. I eventually need to learn how to do this.

    – Josh
    14 mins ago

















I agree. I eventually need to learn how to do this.

– Josh
14 mins ago





I agree. I eventually need to learn how to do this.

– Josh
14 mins ago













3














For what its worth, the function source actually uses eval(parse(...)), albeit in a somewhat subtle way. First, .Internal(parse(...)) is used to create expressions, which after more processing are later passed to eval. So eval(parse(...)) seems to be good enough for the R core team in this instance.



That said, you don't need to jump through hoops to source functions into a new environment. source provides an argument local that can be used for precisely this.




local: TRUE, FALSE or an environment, determining where the parsed expressions are evaluated.




An example:



env = new.env()
source('test.r', local = env)


testing it works:



env$test('hello', 'world')
# [1] "hello world"
ls(pattern = 'test')
# character(0)


And an example test.r file to use this on:



test = function(a,b) paste(a,b)





share|improve this answer
























  • Thank you, I missed that aspect of source(). However, if I change that line of code to source(paste0("C:/Users/JT/R/Functions/", func, ".R"), local = environment) I get the error Error in source(paste0("C:/Users/JT/R/Functions/", func, ".R"), local = environment) : 'local' must be TRUE, FALSE or an environment. Is there a way to convert the "env" that comes from environment to env?

    – Josh
    6 mins ago


















3














For what its worth, the function source actually uses eval(parse(...)), albeit in a somewhat subtle way. First, .Internal(parse(...)) is used to create expressions, which after more processing are later passed to eval. So eval(parse(...)) seems to be good enough for the R core team in this instance.



That said, you don't need to jump through hoops to source functions into a new environment. source provides an argument local that can be used for precisely this.




local: TRUE, FALSE or an environment, determining where the parsed expressions are evaluated.




An example:



env = new.env()
source('test.r', local = env)


testing it works:



env$test('hello', 'world')
# [1] "hello world"
ls(pattern = 'test')
# character(0)


And an example test.r file to use this on:



test = function(a,b) paste(a,b)





share|improve this answer
























  • Thank you, I missed that aspect of source(). However, if I change that line of code to source(paste0("C:/Users/JT/R/Functions/", func, ".R"), local = environment) I get the error Error in source(paste0("C:/Users/JT/R/Functions/", func, ".R"), local = environment) : 'local' must be TRUE, FALSE or an environment. Is there a way to convert the "env" that comes from environment to env?

    – Josh
    6 mins ago
















3












3








3







For what its worth, the function source actually uses eval(parse(...)), albeit in a somewhat subtle way. First, .Internal(parse(...)) is used to create expressions, which after more processing are later passed to eval. So eval(parse(...)) seems to be good enough for the R core team in this instance.



That said, you don't need to jump through hoops to source functions into a new environment. source provides an argument local that can be used for precisely this.




local: TRUE, FALSE or an environment, determining where the parsed expressions are evaluated.




An example:



env = new.env()
source('test.r', local = env)


testing it works:



env$test('hello', 'world')
# [1] "hello world"
ls(pattern = 'test')
# character(0)


And an example test.r file to use this on:



test = function(a,b) paste(a,b)





share|improve this answer













For what its worth, the function source actually uses eval(parse(...)), albeit in a somewhat subtle way. First, .Internal(parse(...)) is used to create expressions, which after more processing are later passed to eval. So eval(parse(...)) seems to be good enough for the R core team in this instance.



That said, you don't need to jump through hoops to source functions into a new environment. source provides an argument local that can be used for precisely this.




local: TRUE, FALSE or an environment, determining where the parsed expressions are evaluated.




An example:



env = new.env()
source('test.r', local = env)


testing it works:



env$test('hello', 'world')
# [1] "hello world"
ls(pattern = 'test')
# character(0)


And an example test.r file to use this on:



test = function(a,b) paste(a,b)






share|improve this answer












share|improve this answer



share|improve this answer










answered 2 hours ago









dwwdww

15.9k32659




15.9k32659













  • Thank you, I missed that aspect of source(). However, if I change that line of code to source(paste0("C:/Users/JT/R/Functions/", func, ".R"), local = environment) I get the error Error in source(paste0("C:/Users/JT/R/Functions/", func, ".R"), local = environment) : 'local' must be TRUE, FALSE or an environment. Is there a way to convert the "env" that comes from environment to env?

    – Josh
    6 mins ago





















  • Thank you, I missed that aspect of source(). However, if I change that line of code to source(paste0("C:/Users/JT/R/Functions/", func, ".R"), local = environment) I get the error Error in source(paste0("C:/Users/JT/R/Functions/", func, ".R"), local = environment) : 'local' must be TRUE, FALSE or an environment. Is there a way to convert the "env" that comes from environment to env?

    – Josh
    6 mins ago



















Thank you, I missed that aspect of source(). However, if I change that line of code to source(paste0("C:/Users/JT/R/Functions/", func, ".R"), local = environment) I get the error Error in source(paste0("C:/Users/JT/R/Functions/", func, ".R"), local = environment) : 'local' must be TRUE, FALSE or an environment. Is there a way to convert the "env" that comes from environment to env?

– Josh
6 mins ago







Thank you, I missed that aspect of source(). However, if I change that line of code to source(paste0("C:/Users/JT/R/Functions/", func, ".R"), local = environment) I get the error Error in source(paste0("C:/Users/JT/R/Functions/", func, ".R"), local = environment) : 'local' must be TRUE, FALSE or an environment. Is there a way to convert the "env" that comes from environment to env?

– Josh
6 mins ago




















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