Progress on preparsing

3 files changed, 350 insertions, 1 deletions

diff --git a/src/dev.ts b/src/dev.ts
index a9b785103..d7a4ec47f 100644
--- a/src/dev.ts
+++ b/src/dev.ts
@@ -35,7 +35,7 @@ export default async function(astroConfig: AstroConfig) {
       [internalPath.pathname]: '/__hmx_internal__'
     },
     plugins: [
-      ['hmx-v2/snowpack-plugin', hmxPlugOptions]
+      ['astro/snowpack-plugin', hmxPlugOptions]
     ],
     devOptions: {
       open: 'none',
diff --git a/src/parser.ts b/src/parser.ts
new file mode 100644
index 000000000..f47486f65
--- /dev/null
+++ b/src/parser.ts
@@ -0,0 +1,304 @@
+const [
+  CHARS,
+  TAG_START,
+  TAG_END,
+  END_TAG_START,
+  EQ,
+  EOF,
+  UNKNOWN
+] = Array.from(new Array(20), (x, i) => i + 1);
+
+const voidTags = new Set(['area', 'base', 'br', 'col', 'command', 'embed', 'hr',
+  'img', 'input', 'keygen', 'link', 'meta', 'param', 'source', 'track', 'wbr']);
+
+type Visitor = (tag: Tag) => Tag;
+
+interface State {
+  code: string;
+  index: number;
+  visitor: Visitor;
+  tagName?: string;
+}
+
+interface Attribute {
+  name: string;
+  value?: string;
+  boolean: boolean;
+  start: number;
+  end: number;
+}
+
+interface Text {
+  type: 0;
+  data: string;
+  start: number;
+  end: number;
+}
+
+export interface Tag {
+  type: 1;
+  tagName: string;
+  attributes: Array<Attribute>;
+  children: Array<Tag | Text>;
+  void: boolean;
+  start: number;
+  end: number;
+}
+
+interface Document {
+  children: Array<Tag | Text>;
+}
+
+function stateChar(state: State) {
+  return state.code[state.index];
+}
+
+function stateNext(state: State) {
+  state.index++;
+  return stateChar(state);
+}
+
+function stateRewind(state: State) {
+  state.index--;
+  return stateChar(state);
+}
+
+function stateInBounds(state: State) {
+  return state.index < state.code.length;
+}
+
+function createState(code: string, visitor: Visitor): State {
+  return {
+    code,
+    index: 0,
+    visitor
+  };
+}
+
+function* _stringify(tag: Tag): Generator<string, void, unknown> {
+  yield '<';
+  yield tag.tagName;
+  for(let attr of tag.attributes) {
+    yield ' ';
+    yield `"${attr.name}"`;
+    if(!attr.boolean) {
+      yield '=';
+      yield `"${attr.value}"`;
+    }
+  }
+  if(!tag.void) {
+    for(let child of tag.children) {
+      if(child.type === 0) {
+        yield child.data;
+      } else {
+        yield * _stringify(child);
+      }
+    }
+  }
+}
+
+function stringify(tag: Tag) {
+  let out = '';
+  for(let chunk of _stringify(tag)) {
+    out += chunk;
+  }
+  return out;
+}
+
+function spliceSlice(str: string, index: number, count: number, add: string) {
+  // We cannot pass negative indexes directly to the 2nd slicing operation.
+  if (index < 0) {
+    index = str.length + index;
+    if (index < 0) {
+      index = 0;
+    }
+  }
+
+  return str.slice(0, index) + (add || "") + str.slice(index + count);
+}
+
+function replaceTag(state: State, tag: Tag) {
+  const origLen = tag.end - tag.start;
+  const html = stringify(tag);
+  const newLen = html.length;
+  const newCurIndex = tag.start + newLen;
+
+  state.code = spliceSlice(state.code, tag.start, origLen, html);
+  state.index = newCurIndex;
+}
+
+function consumeToken(state: State) {
+  do {
+    const c = stateNext(state);
+
+    if(/\s/.test(c)) {
+      continue;
+    }
+
+    if(c === '<') {
+      return TAG_START;
+    }
+
+    if(c === '>') {
+      return TAG_END;
+    }
+
+    if(c === '/') {
+      return END_TAG_START;
+    }
+
+    if(/[a-zA-Z]/.test(c)) {
+      return CHARS;
+    }
+
+    return UNKNOWN;
+  } while(stateInBounds(state));
+
+  return EOF;
+}
+
+function consumeText(state: State): Text {
+  let start = state.index;
+  let data = '';
+  let c = stateNext(state);
+  while(stateInBounds(state) && c !== '<') {
+    data += c;
+    c = stateNext(state);
+  }
+
+  return {
+    type: 0,
+    data,
+    start,
+    end: state.index - 1
+  };
+}
+
+function consumeTagName(state: State): string {
+  let name = '';
+  let token = consumeToken(state);
+  while(token === CHARS) {
+    name += stateChar(state);
+    token = consumeToken(state);
+  }
+  return name.toLowerCase();
+}
+
+function consumeAttribute(state: State): Attribute {
+  let start = state.index;
+  let name = '', token;
+  do {
+    name += stateChar(state).toLowerCase();
+    token = consumeToken(state);
+  } while(token === CHARS);
+
+  if(token !== EQ) {
+    stateRewind(state);
+    return {
+      name,
+      boolean: true,
+      start,
+      end: state.index - 1
+    };
+  }
+
+  let value = '';
+  do {
+    value += stateChar(state).toLowerCase();
+    token = consumeToken(state);
+  } while(token === CHARS);
+
+  return {
+    name,
+    value,
+    boolean: false,
+    start,
+    end: state.index - 1
+  };
+}
+
+function consumeChildren(state: State): Array<Tag | Text> {
+  const children: Array<Tag | Text> = [];
+
+  childLoop: while(stateInBounds(state)) {
+    const token = consumeToken(state);
+    switch(token) {
+      case TAG_START: {
+        const next = consumeToken(state);
+        if(next === END_TAG_START) {
+          consumeTagName(state);
+          consumeToken(state); // >
+          break childLoop;
+        } else {
+          stateRewind(state);
+          consumeTag(state);
+        }
+        break;
+      }
+      case CHARS: {
+        children.push(consumeText(state));
+        break;
+      }
+      default: {
+        break;
+      }
+    }
+  }
+
+  return children;
+}
+
+function consumeTag(state: State): Tag {
+  const start = state.index - 1;
+  const tagName = consumeTagName(state);
+  const attributes: Array<Attribute> = [];
+
+  let token = consumeToken(state);
+
+  // Collect attributes
+  attrLoop: while(token !== TAG_END) {
+    switch(token) {
+      case CHARS: {
+        attributes.push(consumeAttribute(state));
+        break;
+      }
+      default: {
+        break attrLoop;
+      }
+    }
+
+    token = consumeToken(state);
+  }
+
+  const children: Array<Tag | Text> = consumeChildren(state);
+
+  const node: Tag = {
+    type: 1,
+    tagName,
+    attributes,
+    children,
+    void: voidTags.has(tagName),
+    start,
+    end: state.index - 1
+  };
+
+  const replacement = state.visitor(node);
+  if(replacement !== node) {
+    replaceTag(state, node);
+  }
+
+  return node;
+}
+
+function consumeDocument(state: State): Document {
+  const children: Array<Tag | Text> = consumeChildren(state);
+
+  return {
+    children
+  };
+}
+
+export function preparse(code: string, visitor: Visitor) {
+  const state = createState(code, visitor);
+  consumeDocument(state);
+}
\ No newline at end of file
diff --git a/src/transform2.ts b/src/transform2.ts
index 51399a48a..485c575c6 100644
--- a/src/transform2.ts
+++ b/src/transform2.ts
@@ -11,6 +11,7 @@ import matter from "gray-matter";
 import gfmHtml from "micromark-extension-gfm/html.js";
 import { walk, parse } from "./compiler.js";
 import markdownEncode from './markdown-encode.js';
+import { preparse } from './parser.js';
 
 const { transformSync } = esbuild;
 
@@ -161,11 +162,55 @@ function getComponentWrapper(
   throw new Error("Unknown Component Type: " + name);
 }
 
+function runPreparser(template: string): string {
+  const doc = preparse(template, tag => {
+    if(tag.tagName === 'script') {
+      let isSetup = false;
+      for(let attr of tag.attributes) {
+        if(attr.name === 'hmx' && attr.value === 'setup') {
+          isSetup = true;
+          break;
+        }
+      }
+      if(isSetup && typeof tag.children[0] === 'string') {
+        debugger;
+
+        const content = tag.children[0];
+        let { code } = transformSync(content, {
+          loader: "tsx",
+          jsxFactory: "h",
+          jsxFragment: "Fragment",
+          charset: "utf8",
+        });
+        return {
+          ...tag,
+          children: [{
+            type: 0,
+            data: code,
+            start: 0,
+            end: 0
+          }]
+        };
+      }
+    }
+
+    return tag;
+  });
+
+  // TODO codegen
+
+  return template;
+}
+
 async function convertHmxToJsx(template: string, compileOptions: CompileOptions) {
   await eslexer.init;
+
+  //template = runPreparser(template);
+
   const ast = parse(template, {});
   // Todo: Validate that `h` and `Fragment` aren't defined in the script
   const script = ast.instance ? astring.generate(ast.instance.content) : "";
+
   const [scriptImports] = eslexer.parse(script, "optional-sourcename");
   const components = Object.fromEntries(
     scriptImports.map((imp) => {