# Programming functions

These are the programming functions. See each function's help topic in the TERR Language Reference for more information.

Function name | Title description
--- | ---
`...elt` | Manipulate Ellipsis Arguments
`...length` | Manipulate Ellipsis Arguments
`...names` | Manipulate Ellipsis Arguments
`.doTrace` | Trace Calls to Functions
`.GlobalEnv` | Environment Access
`.handleSimpleError` | Condition Handling and Recovery
`.getNamespace` | Get Namespace Environment Information
`.Last.value` | Value of Last Evaluated Expression
`.makeMessage` | Diagnostic Messages
`.packageStartupMessage` | Diagnostic Messages
`.signalSimpleWarning` | Condition Handling and Recovery
`(` | The Structure of Expressions
`[.terms` | Modify Terms Objects
`{` | The Structure of Expressions
`||` | Control Flow
`addTaskCallback` | Manage Top-Level Task Callbacks
`all.names` | Find All Names in an Expression
`all.vars` | Find All Names in an Expression
`as` | Generic Coercion Function
`as.call` | Calling Functions
`as.character.condition` | Condition Handling and Recovery
`as.character.error` | Condition Handling and Recovery
`as.double` | Double Precision Objects
`as.double.difftime` | Double Precision Objects
`as.double.POSIXlt` | Double Precision Objects
`as.expression` | Expression Objects
`as.function` | Function Objects
`as.integer` | Integer Objects
`as.name` | Names and Symbols
`as.symbol` | Names and Symbols
`assign` | Assign Object to Environment
`attachNamespace` | Loading and Unloading Namespaces
`baseenv` | Environment Access
`bquote` | Partial Substitution in Expressions
`break` | Control Flow
`browser` | Browse Interactively in a Function's Frame
`call` | Calling Functions
`charmatch` | Partial Matching of Character Strings
`chkDots` | Manipulate Ellipsis Arguments
`computeRestarts` | Condition Handling and Recovery
`condition` | Condition Handling and Recovery
`conditionCall` | Condition Handling and Recovery
`conditionCall.condition` | Condition Handling and Recovery
`conditionMessage` | Condition Handling and Recovery
`conditionMessage.condition` | Condition Handling and Recovery
`conditions` | Condition Handling and Recovery
`Control` | Control Flow
`delete.response` | Modify Terms Objects
`deparse` | Turn a Parsed Expression into Character Form
`deparse1` | Turn a Parsed Expression into Character Form
`dir` | List the Files in a Directory
`do.call` | Execute a Function Call
`dontCheck` | Return Argument Unaltered
`double` | Double Precision Objects
`drop.terms` | Modify Terms Objects
`else` | Control Flow
`emptyenv` | Environment Access
`environment` | Environment Access
`environment<-` | Environment Access
`environmentName` | Environment Access
`errorCondition` | Condition Handling and Recovery
`eval` | Evaluate an Expression
`eval.parent` | Evaluate an Expression
`evalq` | Evaluate an Expression
`existsFunction` | Get Function from Environment
`expression` | Expression Objects
`Filter` | Common Higher-Order Functions
`Find` | Common Higher-Order Functions
`findRestart` | Condition Handling and Recovery
`for` | Control Flow
`forceAndCall` | Call a Function with Some Arguments Forced
`formals` | Access and Manipulate the Formal Arguments
`formals<-` | Access and Manipulate the Formal Arguments
`function` | The Structure of Expressions
`geterrmessage` | Error and Warning Messages
`getExportedValue` | Get Namespace Environment Information
`getFunction` | Get Function from Environment
`getNamespace` | Get Namespace Environment Information
`getNamespaceExports` | Get Namespace Environment Information
`getNamespaceImports` | Get Namespace Environment Information
`getNamespaceName` | Get Namespace Environment Information
`getNamespaceUsers` | Get Namespace Environment Information
`getNamespaceVersion` | Get Namespace Environment Information
`getTaskCallbackNames` | Manage Top-Level Task Callbacks
`globalenv` | Environment Access
`history` | Print History of Evaluated Expressions
`identity` | Return Argument Unaltered
`if` | Control Flow
`in` | Control Flow
`integer` | Integer Objects
`interactive` | Test For Interactive Execution
`invisible` | Mark Function as Non-Printing
`invokeRestart` | Condition Handling and Recovery
`invokeRestartInteractively` | Condition Handling and Recovery
`is.atomic` | Test for Atomic or Recursive Objects
`is.call` | Calling Functions
`is.double` | Double Precision Objects
`is.environment` | Environment Access
`is.expression` | Expression Objects
`is.function` | Function Objects
`is.integer` | Integer Objects
`is.language` | Test for Atomic or Recursive Objects
`is.name` | Names and Symbols
`is.R` | Test If Running Under an R Compatible Engine
`is.recursive` | Test for Atomic or Recursive Objects
`is.symbol` | Names and Symbols
`isBaseNamespace` | Check if an Environment is a (base) Namespace Environment
`isNamespace` | Check if an Environment is a (base) Namespace Environment
`isNamespaceLoaded` | Get Namespace Environment Information
`isRestart` | Condition Handling and Recovery
`languageEl` | Extract or Replace Parts of Expressions
`list.dirs` | List the Files in a Directory
`list.files` | List the Files in a Directory
`loadedNamespaces` | Loading and Unloading Namespaces
`loadhistory` | Print History of Evaluated Expressions
`loadNamespace` | Loading and Unloading Namespaces
`local` | Evaluate an Expression
`make.names` | Make Character Strings into Legal Names
`make.unique` | Make Character Strings Unique
`Map` | Common Higher-Order Functions
`match.arg` | Verify an Argument Using Partial Matching
`match.call` | Argument Matching
`match.fun` | Function Verification for "Function Variables"
`message` | Diagnostic Messages
`missing` | Check for Missing Arguments
`mode` | Data Mode of the Values in a Vector
`name` | Names and Symbols
`nargs` | Number of Arguments to Function
`Negate` | Common Higher-Order Functions
`new.env` | Environment Access
`next` | Control Flow
`NextMethod` | Methods Invoked from Functions
`on.exit` | Exit Expression For a Function
`packageStartupMessage` | Diagnostic Messages
`parent.env` | Environment Access
`parent.env<-` | Environment Access
`parent.frame` | Get the System Evaluator State
`parse` | Parse Expressions
`Position` | Common Higher-Order Functions
`print.condition` | Condition Handling and Recovery
`print.restart` | Condition Handling and Recovery
`R.version` | Version Information
`R.Version` | Version Information
`R.version.string` | Version Information
`readline` | Read a Line from the Terminal
`readLines` | Read or Write Multiple Lines from or to a Connection
`Recall` | Recursive Call of the Current Function
`Reduce` | Common Higher-Order Functions
`reformulate` | Modify Terms Objects
`reg.finalizer` | Finalization of Objects
`removeTaskCallback` | Manage Top-Level Task Callbacks
`repeat` | Control Flow
`requireNamespace` | Loading and Unloading Namespaces
`restartDescription` | Condition Handling and Recovery
`restartFormals` | Condition Handling and Recovery
`return` | The Structure of Expressions
`S3Part` | S4 Classes that Contain S3 Classes
`savehistory` | Print History of Evaluated Expressions
`setAs` | Generic Coercion Function
`setNamespaceInfo` | Access Namespace Environment Information
`signalCondition` | Condition Handling and Recovery
`simpleCondition` | Condition Handling and Recovery
`simpleError` | Condition Handling and Recovery
`simpleMessage` | Condition Handling and Recovery
`simpleWarning` | Condition Handling and Recovery
`sleep` | Sleep for a Specified Period
`slice.index` | Slice Identification in an Array
`stop` | Error and Warning Messages
`stopifnot` | Stop if Not All True
`storage.mode` | Data Mode of the Values in a Vector
`str2expression` | Parse Expressions
`str2lang` | Parse Expressions
`substitute` | Substitute in an Expression
`substituteDirect` | Substitute in an Expression
`suppressMessages` | Diagnostic Messages
`suppressPackageStartupMessages` | Diagnostic Messages
`suppressWarnings` | Error and Warning Messages
`switch` | Evaluate One of Several Expressions
`Syntax` | The Structure of Expressions
`sys.call` | Get the System Evaluator State
`sys.calls` | Get the System Evaluator State
`sys.frame` | Get the System Evaluator State
`sys.frames` | Get the System Evaluator State
`sys.function` | Get the System Evaluator State
`sys.nframe` | Get the System Evaluator State
`sys.on.exit` | Get the System Evaluator State
`sys.parent` | Get the System Evaluator State
`sys.parents` | Get the System Evaluator State
`Sys.sleep` | Sleep for a Specified Period
`sys.status` | Get the System Evaluator State
`system` | Invoke a System Command
`taskCallbackManager` | Create an R-level Task Callback Manager
`tempdir` | Create Unique Names for Files
`tempfile` | Create Unique Names for Files
`timestamp` | Print History of Evaluated Expressions
`topenv` | Top-Level Environment
`trace` | Trace Calls to Functions
`traceback` | Print Call Stack After Error
`try` | Continue after errors
`tryCatch` | Condition Handling and Recovery
`unimplementedStop` | Functions for Handling Unimplemented Functions and Arguments
`unimplementedWarning` | Functions for Handling Unimplemented Functions and Arguments
`unlink` | Remove Files and Directories
`unloadNamespace` | Loading and Unloading Namespaces
`untrace` | Trace Calls to Functions
`UseMethod` | Methods Invoked from Functions
`version` | Version Information
`warning` | Error and Warning Messages
`warningCondition` | Condition Handling and Recovery
`while` | Control Flow
`with` | Evaluates an expression in a given context
`with.default` | Evaluates an expression in a given context
`withCallingHandlers` | Condition Handling and Recovery
`within` | Evaluates an expression in a given context
`within.data.frame` | Evaluates an expression in a given context
`within.list` | Evaluates an expression in a given context
`withRestarts` | Condition Handling and Recovery
`writeLines` | Read or Write Multiple Lines from or to a Connection