LeMP Namespace Reference

The lexical macro processor. Main classes: LeMP.Compiler and LeMP.MacroProcessor. More...

Namespaces
namespace	Prelude
	Defines prelude macros, which are predefined macros that normally do not have to be explicitly imported before use (in LES or EC#).
namespace	Tests
	Contains tests for the LeMP.MacroProcessor and for standard LeMP macros.

Classes
class	Compiler
	A class that helps you invoke MacroProcessor on on a set of source files, given a set of command-line options. More...
class	ContainsMacrosAttribute
	Marks a class to be searched for macros. More...
interface	IMacroContext
	This interface provides services offered by the lexical macro processor (LeMP). More...
class	InputOutput
	For LeMP: an input file plus per-file options (input and output language) and output code. More...
class	LexicalMacroAttribute
	Marks a method as a LeMP lexical macro. More...
class	MacroContext
	Standard extension methods for IMacroContext. More...
class	MacroInfo
	Data returned from IMacroContext.AllKnownMacros More...
class	MacroProcessor
	Encapsulates the LeMP engine, a simple LISP-style macro processor, suitable for running LLLPG and other lexical macros. More...
class	MacroProcessorTests
class	TestCompiler
	A simple version of Compiler that takes a single input and produces a StringBuilder. Pre-opens LeMP.Prelude namespaces. More...

Typedefs
using	S = CodeSymbols

Enumerations
enum	MacroMode {   MacroMode.Normal = 0, MacroMode.NoReprocessing = 1, MacroMode.ProcessChildrenAfter = 2,   MacroMode.ProcessChildrenBefore = 4, MacroMode.Passive = 8, MacroMode.AllowDuplicates = 16,   MacroMode.DropRemainingListItems = 32, MacroMode.MatchIdentifier = 64, MatchIdentifierOrCall = 64,   MacroMode.MatchIdentifierOnly = 128, MacroMode.MatchEveryLiteral = 0x1000, MacroMode.MatchEveryCall = 0x2000,   MacroMode.MatchEveryIdentifier = 0x4000, MacroMode.UseLogicalNameInErrorMessages = 0x8000, MacroMode.PriorityFallbackMin = 0x100,   MacroMode.PriorityFallback = 0x300, MacroMode.PriorityInternalFallback = 0x400, MacroMode.PriorityNormal = 0x500,   MacroMode.PriorityInternalOverride = 0x600, MacroMode.PriorityOverride = 0x700, MacroMode.PriorityOverrideMax = 0x900,   MacroMode.PriorityMask = 0xF00 }
	Flags that affect the way that LeMP.MacroProcessor uses a LexicalMacro. More...

Functions
delegate LNode	LexicalMacro (LNode node, IMacroContext context)
	Method signature of an LeMP macro. More...

Detailed Description

The lexical macro processor. Main classes: LeMP.Compiler and LeMP.MacroProcessor.

Enumeration Type Documentation

MacroMode

enum LeMP.MacroMode

strong

Flags that affect the way that LeMP.MacroProcessor uses a LexicalMacro.

Enumerator
Normal	The macro's result is reprocessed directly (this is the default behavior).
NoReprocessing	The macro's result (including children) is not processed further. This flag only takes effect when the macro accepts the input by returning a non-null result.
ProcessChildrenAfter	The macro's result is not reprocessed, but the result's children are processed. This flag only takes effect when the macro accepts the input by returning a non-null result.
ProcessChildrenBefore	The result is pre-processed before calling the macro, and not processed afterward (if the macro accepts the input by returning a non-null result).
Passive	It is normal for this macro not to change the code, so a warning should not be printed when the macro "rejects" the input by returning null.
AllowDuplicates	If this macro is ambiguous with one or more macro of the same priority, this flag blocks the ambiguity error message if all the macros produce equivalent results.
DropRemainingListItems	If this macro succeeds, all nodes after this one in the current attribute or statement/argument list are dropped. This option may be used by macros that splice together the list of IMacroContext.RemainingNodes into their own result. It is more common, however, to set the IMacroContext.DropRemainingNodes property inside the macro.
MatchIdentifier	If this flag is present, the macro can match a plain identifier. By default, only calls can be treated as macros. This flag does not prevent the macro from matching calls.
MatchIdentifierOnly	If this flag is present, the macro can match a plain identifier but cannot match calls.
MatchEveryLiteral	The macro will be called whenever any kind of literal is encountered (if its namespace is imported). When a literal is encountered, it is processed as though the Passive flag were present on all macros that use this flag, because no macro should alter all literals.
MatchEveryCall	The macro will be called for every call node (if its namespace is imported). When a macro with this flag is called, it is processed as though the Passive flag were present.
MatchEveryIdentifier	The macro will be called for every identifier node (if its namespace is imported). When a macro with this flag is called, it is processed as though the Passive flag were present.
UseLogicalNameInErrorMessages	Tells LeMP not to mention the physical method that implements the macro. This improves error message clarity for user-defined macros, all of which share a single implementing method.
PriorityFallbackMin	Lowest priority. If this macro is ambiguous with another macro that doesn't have this flag, the results produced by the other macro are used (note: only one priority flag can be used at a time).
PriorityFallback	Low priority. If this macro is ambiguous with another macro that doesn't have this flag nor FallbackMin, the results produced by the other macro are used (note: only one priority flag can be used at a time).
PriorityInternalFallback	Used to order behavior of standard macros.
PriorityNormal	Normal priority (this is the default and does not need to be specified.)
PriorityInternalOverride	Used to order behavior of standard macros.
PriorityOverride	High priority. If this macro is ambiguous with another macro that doesn't have this flag nor OverrideAll, this macro takes precedence (note: only one priority flag can be used at a time).
PriorityOverrideMax	Highest priority. If this macro is ambiguous with another macro that doesn't have this flag, the results produced by this macro are used (note: only one priority flag can be used at a time).
PriorityMask	For internal use to isolate the priority of a macro.

Function Documentation

LexicalMacro()

delegate LNode LeMP.LexicalMacro	(	LNode	node,
		IMacroContext	context
	)

Method signature of an LeMP macro.

Parameters

node

The node that caused the macro to be invoked (includes the name of the macro itself, and any attributes applied to the macro)

context

This is a dual-purpose object. Firstly, this object implements IMessageSink. if the input does not have a valid form, the macro rejects it by returning null. Before returning null, the macro should explain the reason for the rejection (including a pattern that the macro accepts) by writinga message to this object. Secondly, this object contains additional information including the ancestors of the current node and a list of "scoped properties" (see IMacroContext.)

Returns

A node to replace the original node, or null if this macro rejects the input node. Returning null can allow a different macro to accept the node instead.

If there are multiple macros in scope with the same name, they are all called. Macro expansion succeeds if exactly one macro accepts the input. If no macros accept the input, the error message given by each macro is printed; if multiple macros accept the input, an ambiguity error is printed.

When the macro processor scans an assembly looking for macros, it requires ContainsMacrosAttribute on the containing class, and LexicalMacroAttribute on each macro in the class. The macros must be public static methods.

Referenced by LeMP.MacroInfo.GetMacros().