nasa · bocchino · Apr 20, 2026 · Sep 8, 2025 · Sep 10, 2025 · Sep 10, 2025
diff --git a/docs/code-prettify/run_prettify.js b/docs/code-prettify/run_prettify.js
@@ -435,6 +435,7 @@ var IN_GLOBAL_SCOPE = false;
           "event," +
           "every," +
           "exit," +
+          "expand," +
           "external," +
           "fatal," +
           "format," +
@@ -496,6 +497,7 @@ var IN_GLOBAL_SCOPE = false;
           "struct," +
           "sync," +
           "telemetry," +
+          "template," +
           "text," +
           "throttle," +
           "time," +

diff --git a/docs/fpp-spec.html b/docs/fpp-spec.html
diff --git a/docs/fpp-users-guide.html b/docs/fpp-users-guide.html
@@ -5,7 +5,7 @@
 <meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <meta name="generator" content="Asciidoctor 2.0.26">
-<title>The F Prime Prime (FPP) User&#8217;s Guide, v3.2.0</title>
+<title>The F Prime Prime (FPP) User&#8217;s Guide, Unreleased, after v3.2.0</title>
 <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans:300,300italic,400,400italic,600,600italic%7CNoto+Serif:400,400italic,700,700italic%7CDroid+Sans+Mono:400,700">
 <style>
 /*! Asciidoctor default stylesheet | MIT License | https://asciidoctor.org */
@@ -437,7 +437,7 @@
 </head>
 <body class="article toc2 toc-left">
 <div id="header">
-<h1>The F Prime Prime (FPP) User&#8217;s Guide, v3.2.0</h1>
+<h1>The F Prime Prime (FPP) User&#8217;s Guide, Unreleased, after v3.2.0</h1>
 <div id="toc" class="toc2">
 <div id="toctitle">Table of Contents</div>
 <ul class="sectlevel1">
@@ -17089,7 +17089,7 @@ <h3 id="Writing-C-Plus-Plus-Implementations_Serialization-of-FPP-Values">17.4. S
 </div>
 <div id="footer">
 <div id="footer-text">
-Last updated 2026-03-27 10:18:33 -0700
+Last updated 2026-04-20 13:42:58 -0700
 </div>
 </div>
 <script src="code-prettify/run_prettify.js"></script>

diff --git a/docs/spec/Analysis-and-Translation.adoc b/docs/spec/Analysis-and-Translation.adoc
@@ -7,7 +7,10 @@ It usually involves the following steps:
 
 . Lexing and parsing to generate an abstract syntax tree (AST).
 
-. If step (1) succeeded, semantic analysis of the AST.
+. If step (1), succeeded, <<Expansion-of-Templates,analysis and expansion of 
+  templates>> to generate a new AST.
+
+. If step (2) succeeded, semantic analysis of the AST generated in step (2).
 
 === Analysis Tools
 

diff --git a/docs/spec/Definitions-and-Uses.adoc b/docs/spec/Definitions-and-Uses.adoc
@@ -4,9 +4,7 @@
 
 A *use* is a
 <<Scoping-of-Names_Qualified-Identifiers,qualified identifier>>
-that refers to a
-<<Definitions,definition>>
-according to the
+that refers to a <<Definitions,definition>> according to the
 <<Scoping-of-Names_Resolution-of-Qualified-Identifiers,scoping rules for names>>.
 
 A use is a *qualifying use* if it qualifies another use. For example, in
@@ -152,7 +150,7 @@ module M {
 
 An error also occurs if the rules
 for resolving <<Expressions_Dot-Expressions_Semantics,dot expressions>>
-causes an implied constant use to be resolved to a member
+cause an implied constant use to be resolved to a member
 of a struct value instead of a constant definition. For example, suppose this 
 definition exists in the model:
 

diff --git a/docs/spec/Definitions/Introduction.adoc b/docs/spec/Definitions/Introduction.adoc
@@ -2,3 +2,39 @@
 
 A *definition* is a unit of syntax that introduces a name _N_
 and associates some code with _N_.
+
+In FPP, there are two kinds of definitions:
+
+. *Global definitions* that introduce globally visible 
+  <<Scoping-of-Names_Names-of-Definitions,qualified names>>.
+
+. *Bound parameter definitions* introduced by binding
+<<Specifiers_Template-Expansion-Specifiers,template arguments>> to
+<<Template-Parameter-Lists,template parameters>> within
+the scope of an <<Expansion-of-Templates,expanded template>>.
+A bound parameter definition is a pair stem:[(p, A)] consisting of
+a template parameter _p_ and a template argument _A_.
+The name associated with a bound parameter definition stem:[(p, A)]
+is the identifier specified in _p_.
+Bound parameter definitions come into scope
+<<Scoping-of-Names_Resolution-of-Identifiers_Inside-an-Expanded-Template,during 
+template expansion>>.
+
+Within an expanded template, a bound parameter definition may *represent*
+a global definition, either directly or indirectly.
+A bound parameter definition stem:[B = (p, A)] represents
+a global definition _D_ if (1) _A_ 
+<<Scoping-of-Names_Resolution-of-Identifiers,refers to>> _D_ or (2)
+_A_ refers to a bound parameter definition _B'_ that represents _D_.
+
+Not all bound parameter definitions represent global definitions.
+For example, the bound parameter definition
+
+[source,fpp]
+----
+( constant x : U32 , 0 )
+----
+
+does not represent any global definition.
+
+The rest of this section discusses the global definitions.
diff --git a/docs/spec/Definitions/Module-Definitions.adoc b/docs/spec/Definitions/Module-Definitions.adoc
@@ -34,6 +34,10 @@ A module member is one of the following:
 
 * A <<Definitions_Topology-Definitions,topology definition>>
 
+* A <<Definitions_Module-Template-Definitions,module template definition>>
+
+* A <<Specifiers_Template-Expansion-Specifiers,template expansion specifier>>
+
 * A <<Specifiers_Location-Specifiers,location specifier>>
 
 * An <<Definitions_Abstract-Type-Definitions,abstract type definition>>

diff --git a/docs/spec/Definitions/Module-Template-Definitions.adoc b/docs/spec/Definitions/Module-Template-Definitions.adoc
@@ -0,0 +1,95 @@
+=== Module Template Definitions
+
+A *module template definition* associates a name
+with a *module template*.
+A module template is a set of syntactic elements, each of which
+becomes a member of a <<Translation-Units-and-Models_Translation-Units,
+translation unit>> or a
+<<Definitions_Module-Definitions,module definition>>
+at the point where the template is <<Expansion-of-Templates,expanded>>.
+Each template may be expanded any number of times, and
+each expansion creates a distinct set of translation unit
+or module members.
+Templates may have parameters that become bound
+to <<Specifiers_Template-Expansion-Specifiers,arguments>>
+at the point of expansion.
+
+==== Syntax
+
+`module` `template`
+<<Lexical-Elements_Identifiers,_identifier_>>
+_[_
+`(` <<Template-Parameter-Lists,_template-param-list_>> `)`
+_]_
+`{`
+_module-member-sequence_
+`}`
+
+_module-member-sequence_ is identical to the module member sequence
+of a <<Definitions_Module-Definitions,module definition>>.
+
+==== Semantics
+
+The identifier is the name of the template.
+
+No module template definition may be the ancestor in the
+abstract syntax tree of another module template definition
+or of a <<Specifiers_Template-Expansion-Specifiers,template expansion specifier>>.
+This rule ensures that <<Expansion-of-Templates,expanding a template>>
+never causes another template to be defined or another
+template expansion to occur.
+
+Each module template definition _M_ that appears in a model
+must pass the following analysis, regardless of whether it
+is expanded.
+
+. Expand _M_ at the point of the definition of _M_, providing the following
+  <<Specifiers_Template-Expansion-Specifiers,arguments for the template 
+  parameters>>:
+
+.. For each constant template parameter, a literal value of the correct type.
+
+.. For each port interface instance template argument, a component
+   instance definition that minimally satisfies the interface.
+
+.. For each type template argument, an abstract type definition.
+
+. In the expansion _E_, do the following:
+
+.. Construct the <<Definitions-and-Uses_Use-Def-Graph,use-def 
+   graph>>, checking for cycles.
+
+.. Compute the types associated with type definition symbols, enumerated
+   constant symbols, and type names, except that array size expressions
+   and default value expressions are still unevaluated.
+
+.. Perform <<Type-Checking,type checking>>,
+   except that array size expressions and default value expressions in type 
+   definitions are still unevaluated. 
+
+==== Example
+
+[source,fpp]
+----
+template MT(
+    constant baseId: FwIdType
+    instance comDriver: Drv.ByteStreamDriver
+) {
+
+    instance comStub: Svc.ComStub base id \
+        baseId + 0x0800
+
+    topology T {
+        instance comDriver
+        instance comStub
+
+        # Connect to the driver from the parameter list
+        connections Downlink {
+            comStub.drvSendOut      -> comDriver.$send
+            comDriver.sendReturnOut -> comStub.drvSendReturnIn
+            comDriver.ready         -> comStub.drvConnected
+        }
+    }
+
+}
+----