From 01041536b65d9e09ee1b8025a87a7eb9f2f6e25a Mon Sep 17 00:00:00 2001
From: Glen Whitney <glen@studioinfinity.org>
Date: Sun, 3 Sep 2023 10:55:32 -0700
Subject: [PATCH] wip: parser setup, doesn't do much yet

---
 src/index.civet | 74 +++++++++++++++++++++++++++++++++++++------------
 1 file changed, 57 insertions(+), 17 deletions(-)

diff --git a/src/index.civet b/src/index.civet
index 1787c12..285ccc1 100644
--- a/src/index.civet
+++ b/src/index.civet
@@ -1,6 +1,7 @@
 moo from ../deps/moo.js
+import type {Lexer, Token} from ../deps/moo.d.ts
 
-type Tree = {[key:string]: string | Tree}
+type Tree = {[key:string]: (string | Tree)[]}
 
 lexer := moo.compile
    comment:    /#.*?$/
@@ -20,27 +21,66 @@ lexer := moo.compile
    oparen:     '('
    cparen:     ')'
 
-export function tree97(vrml1: string): Tree
-   tree: Tree := {}
-   for tok, index of lexer.reset vrml1
-      if tok.type and tok.type !== 'whitespace' and tok.type !== 'comment'
-         tree[`${index}`] = {tok.type, tok.value}
+export function tree97(vrml1: string)
+   parse lexer.reset vrml1
+
+// separatorIgnore :=
+//   'TextureCoordinate Normal Coordinate Texture Material'.split(' ')
+
+function filtered(stream: Lexer): Token | undefined
+   result .= stream.next()
+   while result and (result.type === 'whitespace' or result.type === 'comment')
+      result = stream.next()
+   result
+
+function parse(stream: Lexer, tree: Tree = {}): Tree
+   deferred: Token[] := []
+   held .= filtered stream // for lookahead
+
+   while next := filtered stream
+      unless held break
+      switch data :=
+            {nt: next.type, nv: next.value, ht: held.type, hv: held.value}
+         {ht: 'word', nt: 'obrace'}
+            switch held.value
+               /(?:Transform)?Separator/
+                  {children, ...context} := tree
+                  subTree := parse(stream, context)
+//  separatorIgnore.map((prop) => subTree.delete prop) // unneeded?
+                  if newKids := subTree.children
+                     if 'children' not in tree then tree.children = []
+                     tree.children.push(`
+                        Transform { children [
+                           ${renderList newKids}
+                        ] }`)
+               /Group|Switch|WWWAnchor/
+                  {children, ...context} := tree
+                  subTree := parse(stream, context)
+                  if newKids := subTree.children
+                     if 'children' not in tree then tree.children = []
+                     tree.children.push(`
+                        Group { children [
+                           ${renderList newKids}
+                        ] }`)
+            held = filtered stream
+         {ht: 'word', hv: 'vertexOrdering', nt: 'word', nv: 'COUNTERCLOCKWISE'}
+            tree.vertexOrdering = ['ccw']
+            held = filtered stream
+         else
+            console.log 'How did I end up with held', held, 'and next', next
+   unless held and held.type === 'cbrace'
+      console.log 'Oddly ended up with held', held
    tree
 
 function render(t: string | Tree): string
    if typeof t is 'string'
       return t
-   result .= ''
-   for item of Object.values t
-      if typeof item is 'string' then result += item + ' '
-      else
-         typ := item.type
-         result += render(typ)
-         if typeof typ === 'string' and
-               ['cbrace', 'cbracket', 'cparen'].includes(typ)
-            result += "\n"
-         else result += ' '
-   result
+   return .= ''
+   for prop in t
+      return.value += ` ${prop}: ${renderList t[prop]}\n`
+
+function renderList(l: (string | Tree)[]): string
+   l.map(render).join(' ')
 
 export function convert(vrml1: string): string
    render tree97 vrml1