Add a QAST::InlinePlaceholder to represent a place in the QAST where an argument needs to be filled in when inlining. Implement a first cut of producing a tree with the placeholders substituted in.

Author: jnthn

src/QAST/IVal.nqp

@@ -1,4 +1,8 @@
 class QAST::IVal is QAST::Node {
     has int $!value;
     method value(*@value) { $!value := @value[0] if @value; $!value }
+    
+    method substitute_inline_placeholders(@fillers) {
+        self
+    }
 }

src/QAST/InlinePlaceholder.nqp

@@ -0,0 +1,15 @@
+# This indicates a place in a QAST tree that has been stashed for later
+# inlining where one of the arguments to the inlined routine was used.
+class QAST::InlinePlaceholder is QAST::Node {
+    has int $!position;
+    
+    method position(*@value) {
+        @value ?? ($!position := @value[0]) !! $!position
+    }
+    
+    method substitute_inline_placeholders(@fillers) {
+        $!position < +@fillers
+            ?? @fillers[$!position]
+            !! nqp::die("Inline placeholder index out of range")
+    }
+}

src/QAST/NVal.nqp

@@ -1,4 +1,8 @@
 class QAST::NVal is QAST::Node {
     has num $!value;
     method value(*@value) { $!value := @value[0] if @value; $!value }
+    
+    method substitute_inline_placeholders(@fillers) {
+        self
+    }
 }

src/QAST/Node.nqp

@@ -100,4 +100,8 @@ class QAST::Node {
             (%uniques{$prefix} := 1);
         $prefix ~ '_' ~ $id
     }
+    
+    method substitute_inline_placeholders(@fillers) {
+        nqp::die(self.HOW.name(self) ~ " does not support inlining");
+    }
 }

src/QAST/Op.nqp

@@ -6,4 +6,15 @@ class QAST::Op is QAST::Node {
     method name(*@value)       { $!name := @value[0] if @value; $!name || "" }
     method op(*@value)         { $!op := @value[0] if @value; $!op }
     method childorder(*@value) { $!childorder := @value[0] if @value; $!childorder || "" }
+    
+    method substitute_inline_placeholders(@fillers) {
+        my $result := pir::repr_clone__PP(self);
+        my $i := 0;
+        my $elems := +@(self);
+        while $i < $elems {
+            $result[$i] := self[$i].substitute_inline_placeholders(@fillers);
+            $i := $i + 1;
+        }
+        $result
+    }
 }

src/QAST/SVal.nqp

@@ -1,4 +1,8 @@
 class QAST::SVal is QAST::Node {
     has str $!value;
     method value(*@value) { $!value := @value[0] if @value; $!value }
+    
+    method substitute_inline_placeholders(@fillers) {
+        self
+    }
 }

src/QAST/Stmt.nqp

@@ -2,4 +2,15 @@ class QAST::Stmt is QAST::Node {
     has $!resultchild;
 
     method resultchild(*@value) { $!resultchild := @value[0] if @value; $!resultchild }
+    
+    method substitute_inline_placeholders(@fillers) {
+        my $result := pir::repr_clone__PP(self);
+        my $i := 0;
+        my $elems := +@(self);
+        while $i < $elems {
+            $result[$i] := self[$i].substitute_inline_placeholders(@fillers);
+            $i := $i + 1;
+        }
+        $result
+    }
 }

src/QAST/Stmts.nqp

@@ -2,4 +2,15 @@ class QAST::Stmts is QAST::Node {
     has $!resultchild;
 
     method resultchild(*@value) { $!resultchild := @value[0] if @value; $!resultchild }
+    
+    method substitute_inline_placeholders(@fillers) {
+        my $result := pir::repr_clone__PP(self);
+        my $i := 0;
+        my $elems := +@(self);
+        while $i < $elems {
+            $result[$i] := self[$i].substitute_inline_placeholders(@fillers);
+            $i := $i + 1;
+        }
+        $result
+    }
 }

src/QAST/Var.nqp

@@ -10,4 +10,8 @@ class QAST::Var is QAST::Node {
     method decl(*@value)    { $!decl := @value[0] if @value; $!decl }
     method slurpy(*@value)  { $!slurpy := @value[0] if @value; $!slurpy }
     method default(*@value) { $!default := @value[0] if @value; $!default }
+    
+    method substitute_inline_placeholders(@fillers) {
+        self
+    }
 }

src/QAST/WVal.nqp

@@ -4,4 +4,8 @@ class QAST::WVal is QAST::Node does QAST::CompileTimeValue {
             ?? self.set_compile_time_value(@value[0])
             !! self.compile_time_value()
     }
+    
+    method substitute_inline_placeholders(@fillers) {
+        self
+    }
 }