From 547576de00e621ca1273231bcfb3d165af83bbc6 Mon Sep 17 00:00:00 2001
From: "Johan B.W. de Vries" <info@jbwdevries.nl>
Date: Sat, 3 Apr 2021 12:26:06 +0200
Subject: [PATCH] New repo, containing the basic idea

---
 Makefile   |   8 ++++
 compile.py | 133 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 func.html  |  20 ++++++++
 log.html   |  29 ++++++++++++
 log.py     |   5 ++
 5 files changed, 195 insertions(+)
 create mode 100644 Makefile
 create mode 100644 compile.py
 create mode 100644 func.html
 create mode 100644 log.html
 create mode 100644 log.py

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..58bd1f5
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,8 @@
+%.wat: %.py compile.py
+	python3.8 compile.py $< > $@
+
+%.wasm: %.wat
+	wat2wasm $^ -o $@
+
+server:
+	python3.8 -m http.server
diff --git a/compile.py b/compile.py
new file mode 100644
index 0000000..6720a4a
--- /dev/null
+++ b/compile.py
@@ -0,0 +1,133 @@
+import _ast
+import ast
+import sys
+
+class Import:
+    def __init__(self, module, name, intname):
+        self.module = module
+        self.name = name
+        self.intname = intname
+        self.params = None
+
+    def generate(self):
+        return '(import "{}" "{}" (func ${}{}))'.format(
+            self.module,
+            self.name,
+            self.intname,
+            ''.join(' (param {})'.format(x) for x in self.params)
+        )
+
+class Statement:
+    def __init__(self, name, *args):
+        self.name = name
+        self.args = args
+
+    def generate(self):
+        return '{} {}'.format(self.name, ' '.join(self.args))
+
+class Function:
+    def __init__(self, name, exported=True):
+        self.name = name
+        self.exported = exported # TODO: Use __all__!
+        self.statements = []
+
+    def generate(self):
+        return '(func {}\n    {})'.format(
+            ('(export "{}")' if self.exported else '${}').format(self.name),
+            '\n    '.join(x.generate() for x in self.statements),
+        )
+
+class Visitor(ast.NodeVisitor):
+    def __init__(self):
+        self._stack = []
+        self.imports = []
+        self.functions = []
+
+    def visit_ImportFrom(self, node):
+        for alias in node.names:
+            self.imports.append(Import(
+                node.module,
+                alias.name,
+                alias.asname,
+            ))
+
+    def visit_FunctionDef(self, node):
+        func = Function(
+            node.name,
+        )
+
+        self._stack.append(func)
+        self.generic_visit(node)
+        self._stack.pop()
+
+        self.functions.append(func)
+
+    def visit_Expr(self, node):
+        self.generic_visit(node)
+
+    def visit_Call(self, node):
+        self.generic_visit(node)
+
+        func = self._stack[-1]
+        func.statements.append(
+            Statement('call', '$' + node.func.id)
+        )
+
+    def visit_BinOp(self, node):
+        self.generic_visit(node)
+
+        func = self._stack[-1]
+
+        if 'Add' == node.op.__class__.__name__:
+            func.statements.append(
+                Statement('i32.add')
+            )
+        elif 'Mult' == node.op.__class__.__name__:
+            func.statements.append(
+                Statement('i32.mul')
+            )
+        else:
+            err(node.op)
+
+    def visit_Constant(self, node):
+        if not self._stack:
+            # Constant outside of any function
+            imp = self.imports[-1]
+            prefix = imp.name + '('
+            val = node.value.strip()
+
+            if val.startswith(prefix) and val.endswith(')'):
+                imp.params = val[len(prefix):-1].split(',')
+        else:
+            func = self._stack[-1]
+            if isinstance(node.value, int):
+                func.statements.append(
+                    Statement('i32.const', str(node.value))
+                )
+
+        self.generic_visit(node)
+
+    def generate(self):
+        return '(module\n  {}\n  {})'.format(
+            '\n  '.join(x.generate() for x in self.imports),
+            '\n  '.join(x.generate() for x in self.functions),
+        )
+
+def err(msg: str) -> None:
+    sys.stderr.write('{}\n'.format(msg))
+
+def main(source: str) -> int:
+    with open(source, 'r') as fil:
+        code = fil.read()
+
+    res = ast.parse(code, source)
+
+    visitor = Visitor()
+    visitor.visit(res)
+
+    print(visitor.generate())
+
+    return 0
+
+if __name__ == '__main__':
+    sys.exit(main(*sys.argv[1:]))
diff --git a/func.html b/func.html
new file mode 100644
index 0000000..4967ac5
--- /dev/null
+++ b/func.html
@@ -0,0 +1,20 @@
+<!doctype html>
+
+<html>
+
+  <head>
+    <meta charset="utf-8">
+    <title>Simple add example</title>
+  </head>
+
+  <body>
+    <script>
+
+    WebAssembly.instantiateStreaming(fetch('func.wasm'))
+    .then(obj => {
+       console.log(obj.instance.exports.add(1, 2));  // "3"
+    });
+    </script>
+  </body>
+
+</html>
diff --git a/log.html b/log.html
new file mode 100644
index 0000000..8f97d5d
--- /dev/null
+++ b/log.html
@@ -0,0 +1,29 @@
+<!doctype html>
+
+<html>
+
+  <head>
+    <meta charset="utf-8">
+    <title>Simple log example</title>
+  </head>
+
+  <body>
+    <script>
+
+    var importObject = {
+      console: {
+        log: function(arg) {
+          console.log(arg);
+        }
+      }
+    };
+
+    WebAssembly.instantiateStreaming(fetch('log.wasm'), importObject)
+      .then(obj => {
+        obj.instance.exports.logIt();
+      });
+
+    </script>
+  </body>
+
+</html>
diff --git a/log.py b/log.py
new file mode 100644
index 0000000..85f29fd
--- /dev/null
+++ b/log.py
@@ -0,0 +1,5 @@
+from console import log as log
+"log(i32)"
+
+def logIt():
+    log(13 + 13 * 123)