\#macro {name} [once] ([{parameters}]) [> {output path}]
macro value (i.e. fsh text)
\#end

#macro SetComponent(SliceName, Cardinality, ValueSet)
  #apply GraphLink("focus")
  * component[SliceName].value[x] Cardinality
  * component[SliceName].value[x] only CodeableConcept
  * component[SliceName].value[x] from ValueSet
#end

//
// Write out an intro doc.
//
#macro IntroDoc(%Description%) > "%PageContent%\\StructureDefinition-%Id%-intro.xml"
  ` <div xmlns="http://www.w3.org/1999/xhtml"
  `     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  `     xsi:schemaLocation="http://hl7.org/fhir ../../src-generated/schemas/fhir-single.xsd">
  `   <p>
  `     <u style="font-size:large;">Description</u>
  `   </p>
  `   %Description%
  ` </div>
#end

\#apply {name} ([{parameters}])

#apply SetComponent("mySlice", "0..1", "MyValueSet")
#end

#apply SetComponent(
#  """
#  mySlice
#  """,
# "0..1",
# "MyValueSet")

\#incompatible {name}

| name | meaning |
| ---- | -------------- |
| {name}| name of the macro that is being declatred as incompatible |

#### use

The use macro defines a name that will be used in searching for macros (i.e. when calling using \#apply).

A macro name can be defines with periods in the name delimiting the name int seperate pseudo namespaces.

#macro Alpha.Beta.Delta()

The macro can be referenced by its full name

#apply Alpha.Beta.Delta()

or you can use the short cut.

#use Alpha
#apply Beta.Delta()

#use Alpha.Beta
#apply Delta()

A use statement is valid for the whole file.

### FSH Text

Lines that do not start with a '#' are processed as fsh (or json/text if in a macro redirect).
MFSH will replace any variables references in these lines with the variable value.

### Variable Expansion
Variables can be defined which can be referenced in redirect paths, mfsh commands, and fsh text. When a string matching the variable is detected,
the value of the variable will replace the actual variable name.

There are two types of variables.

%{name}%

variables that start and end with '%' will be expanded whereever they are found

{name}

variables that do not start and end with '%' will be expanded only if they are seperate words.

i.e. if a variable xxyyz is defined, then the string

ABCxxyyzDEF

will not have xxyyz relaced,

ABC xxyyz DEF

will have its variable replaced.

### Variables
The following variables are automatically defined.

| name | meaning |
| ---- | -------------- |

| %ApplySourceFile% | The source file that contained the last #apply command executed. Used for debug tracing.
  ApplySourceFile uses unix forward slash directory seperators, not windows backwards slash. |
| %ApplyLineNumber% | The line number in the file that contained the last #apply command executed. Used for debug tracing |
| %ApplyStackFrame% | Apply stack trace (all the apply's command leading up to current context) |
| %BasePath% | The current input file path (relative to the base input directory) |
| %BaseDir% |  The current input file directory (relative to the base input directory)|
| %BaseName% |  The current input file name (no directory) |
| %BaseNameNoExtension% |  The current input file name (no directory, no extension) |

| %MacroName% | The name of the current macro |
| %MacroPath% | The path to the file containing the current macro |
| %MacroDir% | The name of the directory containing the current macro file |
| %MacroFileName% | The file name of the current macro file |
| %MacroFileNameNoExtension% | The file name of the current macro file |

| %SavePath% | The output file path, relative to the base output directory |
| %Id% | Fsh Id header value. This is the name of the current Profile or Extension|
| %Title% | Fsh Title header value. This is the title of the current Profile or Extension|
| %Url% | The name of the current Extension's or Profile's FHIR url. |










#### #if

Con ditionally include element.
The syntax of the command is

```text
\#if {condition}
Fsh/Mfsh lines
\#else if {condition}
Fsh/Mfsh lines
...
\#else
Fsh/Mfsh lines
\#end

#if "mySlice" == "MyValueSet"
...
#end

#if Counter == 10
...
#end