diff --git a/examples/strings.bl b/examples/strings.bl
index bbc4877..2178a5d 100644
--- a/examples/strings.bl
+++ b/examples/strings.bl
@@ -1,5 +1,9 @@
-
-
 fn main(): String {
-    return "foo";
+  let a = 2;
+  a;
+  a = 3;
+  a = if(true) {"asdf"} else {"fdsa"};
+  a.b.c.d();
+  a = (b + c.d()); // comment
+  return a.b() ;
 }
diff --git a/packages/boringlang/src/commands/run.ts b/packages/boringlang/src/commands/run.ts
new file mode 100644
index 0000000..2298e78
--- /dev/null
+++ b/packages/boringlang/src/commands/run.ts
@@ -0,0 +1,29 @@
+import { defineCommand } from "@bunli/core";
+import { boringGrammar } from "../parse/grammar";
+import { semantics } from "../parse/semantics";
+
+export const run = defineCommand({
+  name: "run",
+  description: "Run a boringlang file",
+
+  handler: async ({ positional }) => {
+    const [path] = positional;
+
+    if (!path) {
+      throw new Error("Usage: run <path>");
+    }
+
+    const file = Bun.file(path);
+    const text = await file.text();
+
+    const match = boringGrammar.match(text, "Module");
+    if (match.succeeded()) {
+      const adapter = semantics(match);
+      const ast = adapter.toAST();
+      console.log(JSON.stringify(ast, null, 2));
+    } else {
+      console.log(match.message);
+      // console.log(boringGrammar.trace(text, "Module").toString());
+    }
+  },
+});
diff --git a/packages/boringlang/src/index.ts b/packages/boringlang/src/index.ts
index b3b20f5..0dcdf16 100644
--- a/packages/boringlang/src/index.ts
+++ b/packages/boringlang/src/index.ts
@@ -1,11 +1,14 @@
 #!/usr/bin/env bun
 import { createCLI } from "@bunli/core";
 
+import { run } from "./commands/run.js";
+
 const cli = createCLI({
   name: "boringlang",
   version: "0.1.0",
   description: "Boring programming language CLI",
 });
 
+cli.command(run);
 
 await cli.run();
diff --git a/packages/boringlang/src/parse/ast.ts b/packages/boringlang/src/parse/ast.ts
new file mode 100644
index 0000000..6fb721b
--- /dev/null
+++ b/packages/boringlang/src/parse/ast.ts
@@ -0,0 +1,194 @@
+export interface Spanned {
+  spanStart: number;
+  spanEnd: number;
+}
+
+export interface Identifier extends Spanned {
+  name: string;
+}
+
+export interface LiteralInt {
+  expressionType: "LiteralInt";
+  value: string;
+  type: TypeUsage;
+}
+
+export interface LiteralFloat {
+  expressionType: "LiteralFloat";
+  value: string;
+  type: TypeUsage;
+}
+
+export interface LiteralBool {
+  expressionType: "LiteralBool";
+  value: string;
+  type: TypeUsage;
+}
+
+export interface LiteralString {
+  expressionType: "LiteralString";
+  value: string;
+  type: TypeUsage;
+}
+
+export interface StructField {
+  name: Identifier;
+  expression: Expression;
+}
+
+export interface LiteralStruct {
+  expressionType: "LiteralStruct";
+  name: Identifier;
+  fields: StructField[];
+  type: TypeUsage;
+}
+
+export interface FunctionCall {
+  expressionType: "FunctionCall";
+  source: Expression;
+  arguments: Expression[];
+  type: TypeUsage;
+}
+
+export interface StructGetter {
+  expressionType: "StructGetter";
+  source: Expression;
+  attribute: Identifier;
+  type: TypeUsage;
+}
+
+export interface Operation {
+  expressionType: "Operation";
+  left: Expression;
+  op: "+" | "-" | "*" | "/";
+  right: Expression;
+}
+
+export interface VariableUsage {
+  expressionType: "VariableUsage";
+  name: Identifier;
+  type: TypeUsage;
+}
+
+export interface IfExpression {
+  expressionType: "IfExpression";
+  condition: Expression;
+  block: Block;
+  else: Block | null;
+  type: TypeUsage;
+}
+
+export interface Expression {
+  statementType: "Expression";
+  subExpression:
+    | LiteralInt
+    | LiteralFloat
+    | LiteralBool
+    | LiteralString
+    | LiteralStruct
+    | FunctionCall
+    | VariableUsage
+    | IfExpression
+    | StructGetter
+    | Block
+    | Operation;
+  type: TypeUsage;
+}
+
+export interface ReturnStatement {
+  statementType: "ReturnStatement";
+  source: Expression;
+}
+
+export interface LetStatement {
+  statementType: "LetStatement";
+  variableName: Identifier;
+  expression: Expression;
+  type: TypeUsage;
+}
+
+export interface AssignmentStatement {
+  statementType: "AssignmentStatement";
+  source: VariableUsage | StructGetter;
+  expression: Expression;
+}
+
+export type Statement =
+  | ReturnStatement
+  | LetStatement
+  | AssignmentStatement
+  | Expression;
+
+export interface Block {
+  statements: Statement[];
+  type: TypeUsage;
+}
+
+export interface FunctionArgument {
+  name: Identifier;
+  type: TypeUsage;
+}
+
+export interface FunctionDeclaration {
+  name: Identifier;
+  arguments: FunctionArgument[];
+  returnType: TypeUsage;
+}
+
+export interface Function {
+  moduleItem: "Function";
+  declaration: FunctionDeclaration;
+  block: Block;
+}
+
+export interface StructTypeField {
+  name: Identifier;
+  type: TypeUsage;
+}
+
+export interface StructTypeDeclaration {
+  moduleItem: "StructTypeDeclaration";
+  typeDeclaration: "StructTypeDeclaration";
+  name: Identifier;
+  fields: StructTypeField[];
+}
+
+export interface TraitTypeDeclaration {
+  moduleItem: "TraitTypeDeclaration";
+  typeDeclaration: "TraitTypeDeclaration";
+  name: Identifier;
+  functions: FunctionDeclaration[];
+}
+
+export type TypeDeclaration = StructTypeDeclaration | TraitTypeDeclaration;
+
+export interface Impl {
+  moduleItem: "Impl";
+  struct: NamedTypeUsage;
+  trait: NamedTypeUsage | null;
+  functions: Function[];
+}
+
+export type ModuleItem = Function | TypeDeclaration | Impl;
+
+export interface Module {
+  items: ModuleItem[];
+}
+
+export interface NamedTypeUsage {
+  typeUsage: "NamedTypeUsage";
+  name: Identifier;
+}
+
+export interface FunctionTypeUsage {
+  typeUsage: "FunctionTypeUsage";
+  arguments: TypeUsage[];
+  returnType: TypeUsage;
+}
+
+export interface UnknownTypeUsage {
+  typeUsage: "UnknownTypeUsage";
+  name: string;
+}
+
+export type TypeUsage = NamedTypeUsage | FunctionTypeUsage | UnknownTypeUsage;
diff --git a/packages/boringlang/src/parse/grammar.ts b/packages/boringlang/src/parse/grammar.ts
new file mode 100644
index 0000000..53d49a8
--- /dev/null
+++ b/packages/boringlang/src/parse/grammar.ts
@@ -0,0 +1,66 @@
+import * as ohm from "ohm-js";
+
+export const boringGrammar = ohm.grammar(String.raw`
+  Boringlang {
+    ReturnStatement       = "return" Expression ";"
+    LetStatement          = "let" Identifier (":" TypeUsage)? "=" Expression ";"
+    AssignmentStatement   = VariableUsage "=" Expression ";"
+                          | StructGetter "=" Expression ";"
+    ExpressionStatement   = Expression ";"
+    Statement             = ExpressionStatement
+                          | LetStatement
+                          | ReturnStatement
+                          | AssignmentStatement
+    LiteralInt            = digit+
+    LiteralFloat          = digit* "." digit+
+    LiteralBool           = "true" | "false"
+    LiteralString         = "\"" (~"\"" any)* "\""
+                          | "'" (~"'" any)* "'"
+    LiteralStructField    = Identifier ":" Expression
+    LiteralStruct         = Identifier "{" ListOf<LiteralStructField, ","> "}"
+    Identifier            = (letter | "_")+ (letter | digit | "_")*
+    FunctionCall          = Expression "(" ListOf<Expression, ","> ")"
+    StructGetter          = Expression "." Identifier
+    VariableUsage         = Identifier
+    IfExpression          = "if" "(" Expression ")" Block ("else" Block)?
+    Term                  = LiteralInt
+                          | LiteralFloat
+                          | LiteralBool
+                          | LiteralString
+                          | LiteralStruct
+                          | IfExpression
+                          | Block
+                          | "(" Expression ")" -- parens
+                          | VariableUsage
+    Factor                = Factor "*" Term -- mult
+                          | Factor "/" Term -- div
+                          | Term
+    Expression            = Expression "+" Factor -- plus
+                          | Expression "-" Factor -- minus
+                          | StructGetter
+                          | FunctionCall
+                          | Factor
+    Block                 = "{" Statement* Expression? "}"
+    NamedTypeUsage        = Identifier
+    TypeUsage             = NamedTypeUsage
+                          | "fn" "(" ListOf<TypeUsage, ","> ")" ":" TypeUsage -- function_tu
+    FunctionArgument      = Identifier ":" TypeUsage
+    FunctionDeclaration   = "fn" Identifier "(" ListOf<FunctionArgument, ","> ")" ":" TypeUsage
+    Function              = FunctionDeclaration Block
+    StructTypeField       = Identifier ":" TypeUsage
+    StructTypeDeclaration = "type" Identifier "struct" "{" ListOf<StructTypeField, ","> "}"
+    TraitMethod           = FunctionDeclaration ";"
+    TraitTypeDeclaration  = "type" Identifier "trait" "{" TraitMethod* "}"
+    TypeDeclaration       = StructTypeDeclaration
+                          | TraitTypeDeclaration
+    Impl                  = "impl" (NamedTypeUsage "for")? NamedTypeUsage "{" Function* "}"
+    ModuleItem            = Function
+                          | TypeDeclaration
+                          | Impl
+    Module                = ModuleItem*
+
+    lineTerminator        = "\n" | "\r" | "\u2028" | "\u2029"
+    comment               = "//" (~lineTerminator any)* lineTerminator
+    space                += comment
+  }
+`);
diff --git a/packages/boringlang/src/parse/semantics.ts b/packages/boringlang/src/parse/semantics.ts
new file mode 100644
index 0000000..baf79f3
--- /dev/null
+++ b/packages/boringlang/src/parse/semantics.ts
@@ -0,0 +1,335 @@
+import {
+  AssignmentStatement,
+  Block,
+  Expression,
+  Function,
+  FunctionArgument,
+  FunctionCall,
+  FunctionDeclaration,
+  FunctionTypeUsage,
+  Identifier,
+  IfExpression,
+  Impl,
+  LetStatement,
+  LiteralBool,
+  LiteralFloat,
+  LiteralInt,
+  LiteralString,
+  LiteralStruct,
+  Module,
+  ModuleItem,
+  NamedTypeUsage,
+  Operation,
+  ReturnStatement,
+  Statement,
+  StructField,
+  StructGetter,
+  StructTypeDeclaration,
+  StructTypeField,
+  TraitTypeDeclaration,
+  TypeDeclaration,
+  TypeUsage,
+  VariableUsage,
+} from "./ast";
+import { boringGrammar } from "./grammar";
+
+let unknownTypeCounter = 0;
+function nextUnknown() {
+  let name = "S" + unknownTypeCounter.toString();
+  unknownTypeCounter += 1;
+  return name;
+}
+
+export const semantics = boringGrammar.createSemantics();
+semantics.addOperation<any>("toAST", {
+  LiteralInt(a): LiteralInt {
+    console.log(this);
+    console.log(a.source.startIdx);
+    return {
+      expressionType: "LiteralInt",
+      value: this.sourceString,
+      type: {
+        typeUsage: "NamedTypeUsage",
+        name: { name: "i64", spanStart: 0, spanEnd: 0 },
+      },
+    };
+  },
+  LiteralFloat(_1, _2, _3): LiteralFloat {
+    return {
+      expressionType: "LiteralFloat",
+      value: this.sourceString,
+      type: {
+        typeUsage: "NamedTypeUsage",
+        name: { name: "f64", spanStart: 0, spanEnd: 0 },
+      },
+    };
+  },
+  LiteralBool(_): LiteralBool {
+    return {
+      expressionType: "LiteralBool",
+      value: this.sourceString,
+      type: {
+        typeUsage: "NamedTypeUsage",
+        name: { name: "bool", spanStart: 0, spanEnd: 0 },
+      },
+    };
+  },
+  LiteralString(_1, text, _3): LiteralString {
+    return {
+      expressionType: "LiteralString",
+      value: text.sourceString,
+      type: {
+        typeUsage: "NamedTypeUsage",
+        name: { name: "String", spanStart: 0, spanEnd: 0 },
+      },
+    };
+  },
+  LiteralStructField(identifier, _2, expression): StructField {
+    return {
+      name: identifier.toAST(),
+      expression: expression.toAST(),
+    };
+  },
+  LiteralStruct(identifier, _2, fields, _4): LiteralStruct {
+    return {
+      expressionType: "LiteralStruct",
+      name: identifier.toAST(),
+      fields: fields.asIteration().children.map((c) => c.toAST()),
+      type: { typeUsage: "NamedTypeUsage", name: identifier.toAST() },
+    };
+  },
+  Identifier(_1, _2): Identifier {
+    return {
+      name: this.sourceString,
+      spanStart: this.source.startIdx,
+      spanEnd: this.source.endIdx,
+    };
+  },
+  FunctionCall(expression, _2, args, _4): FunctionCall {
+    return {
+      expressionType: "FunctionCall",
+      source: expression.toAST(),
+      arguments: args.asIteration().children.map((c) => c.toAST()),
+      type: { typeUsage: "UnknownTypeUsage", name: nextUnknown() },
+    };
+  },
+  StructGetter(expression, _2, identifier): StructGetter {
+    return {
+      expressionType: "StructGetter",
+      source: expression.toAST(),
+      attribute: identifier.toAST(),
+      type: { typeUsage: "UnknownTypeUsage", name: nextUnknown() },
+    };
+  },
+  VariableUsage(identifier): VariableUsage {
+    return {
+      expressionType: "VariableUsage",
+      name: identifier.toAST(),
+      type: { typeUsage: "UnknownTypeUsage", name: nextUnknown() },
+    };
+  },
+  IfExpression(_1, _2, expression, _4, block, _6, elseBlock): IfExpression {
+    const eb = elseBlock.toAST();
+    return {
+      expressionType: "IfExpression",
+      condition: expression.toAST(),
+      block: block.toAST(),
+      else: eb.length > 0 ? eb[0] : null,
+      type: { typeUsage: "UnknownTypeUsage", name: nextUnknown() },
+    };
+  },
+  Term(term): Expression {
+    return term.toAST();
+  },
+  Term_parens(_1, term, _3): Expression {
+    return term.toAST();
+  },
+  Factor(factor): Expression {
+    return factor.toAST();
+  },
+  Expression(expression): Expression {
+    return expression.toAST();
+  },
+  Expression_plus(expression, _2, factor): Operation {
+    return {
+      expressionType: "Operation",
+      left: expression.toAST(),
+      op: "+",
+      right: factor.toAST(),
+    };
+  },
+  Expression_minus(expression, _2, factor): Operation {
+    return {
+      expressionType: "Operation",
+      left: expression.toAST(),
+      op: "-",
+      right: factor.toAST(),
+    };
+  },
+  Factor_mult(factor, _2, term): Operation {
+    return {
+      expressionType: "Operation",
+      left: factor.toAST(),
+      op: "*",
+      right: term.toAST(),
+    };
+  },
+  Factor_div(factor, _2, term): Operation {
+    return {
+      expressionType: "Operation",
+      left: factor.toAST(),
+      op: "/",
+      right: term.toAST(),
+    };
+  },
+  Statement(statement): Statement {
+    return statement.toAST();
+  },
+  ReturnStatement(_1, expression, _3): ReturnStatement {
+    return {
+      statementType: "ReturnStatement",
+      source: expression.toAST(),
+    };
+  },
+  LetStatement(_1, ident, _3, typeUsage, _5, expression, _7): LetStatement {
+    const tu = typeUsage.toAST();
+    return {
+      statementType: "LetStatement",
+      variableName: ident.toAST(),
+      expression: expression.toAST(),
+      type:
+        tu.length > 0
+          ? tu[0]
+          : { typeUsage: "UnknownTypeUsage", name: nextUnknown() },
+    };
+  },
+  AssignmentStatement(variable, _2, expression, _4): AssignmentStatement {
+    return {
+      statementType: "AssignmentStatement",
+      source: variable.toAST(),
+      expression: expression.toAST(),
+    };
+  },
+  ExpressionStatement(expression, _2): Expression {
+    return {
+      statementType: "Expression",
+      subExpression: expression.toAST(),
+      type: { typeUsage: "UnknownTypeUsage", name: nextUnknown() },
+    };
+  },
+  Block(_1, statements, expression, _4): Block {
+    const lines = statements.asIteration().children.map((c) => c.toAST());
+    const finalExpression = expression.toAST();
+    lines.push(finalExpression.length > 0 ? finalExpression[0] : null);
+    return {
+      statements: lines,
+      type: { typeUsage: "UnknownTypeUsage", name: nextUnknown() },
+    };
+  },
+  NamedTypeUsage(name): NamedTypeUsage {
+    return {
+      typeUsage: "NamedTypeUsage",
+      name: name.toAST(),
+    };
+  },
+  TypeUsage_function_tu(_1, _2, args, _4, _5, returnType): FunctionTypeUsage {
+    return {
+      typeUsage: "FunctionTypeUsage",
+      arguments: args.asIteration().children.map((c) => c.toAST()),
+      returnType: returnType.toAST(),
+    };
+  },
+  TypeUsage(typeUsage): TypeUsage {
+    return typeUsage.toAST();
+  },
+  FunctionArgument(identifier, _2, typeUsage): FunctionArgument {
+    return {
+      name: identifier.toAST(),
+      type: typeUsage.toAST(),
+    };
+  },
+  FunctionDeclaration(
+    _1,
+    identifier,
+    _3,
+    args,
+    _4,
+    _5,
+    returnType,
+  ): FunctionDeclaration {
+    return {
+      name: identifier.toAST(),
+      arguments: args.asIteration().children.map((c) => c.toAST()),
+      returnType: returnType.toAST(),
+    };
+  },
+  Function(declaration, block): Function {
+    return {
+      moduleItem: "Function",
+      declaration: declaration.toAST(),
+      block: block.toAST(),
+    };
+  },
+  StructTypeField(identifier, _2, typeUsage): StructTypeField {
+    return {
+      name: identifier.toAST(),
+      type: typeUsage.toAST(),
+    };
+  },
+  StructTypeDeclaration(
+    _1,
+    identifier,
+    _3,
+    _4,
+    fields,
+    _6,
+  ): StructTypeDeclaration {
+    return {
+      moduleItem: "StructTypeDeclaration",
+      typeDeclaration: "StructTypeDeclaration",
+      name: identifier.toAST(),
+      fields: fields.asIteration().children.map((c) => c.toAST()),
+    };
+  },
+  TraitMethod(declaration, _2): FunctionDeclaration {
+    return declaration.toAST();
+  },
+  TraitTypeDeclaration(
+    _1,
+    identifier,
+    _3,
+    _4,
+    methods,
+    _5,
+  ): TraitTypeDeclaration {
+    return {
+      moduleItem: "TraitTypeDeclaration",
+      typeDeclaration: "TraitTypeDeclaration",
+      name: identifier.toAST(),
+      functions: methods.asIteration().children.map((c) => c.toAST()),
+    };
+  },
+  TypeDeclaration(declaration): TypeDeclaration {
+    return declaration.toAST();
+  },
+  Impl(_1, trait, _3, struct, _4, methods, _5): Impl {
+    const tr = trait.toAST();
+    return {
+      moduleItem: "Impl",
+      struct: struct.toAST(),
+      trait: tr.length > 0 ? tr[0] : null,
+      functions: methods.asIteration().children.map((c) => c.toAST()),
+    };
+  },
+  ModuleItem(item): ModuleItem {
+    return item.toAST();
+  },
+  Module(items): Module {
+    return {
+      items: items.asIteration().children.map((c) => c.toAST()),
+    };
+  },
+  _iter(...children) {
+    return children.map((c) => c.toAST());
+  },
+});
diff --git a/prettier.config.ts b/prettier.config.js
similarity index 61%
rename from prettier.config.ts
rename to prettier.config.js
index 40065a0..a3ba494 100644
--- a/prettier.config.ts
+++ b/prettier.config.js
@@ -1,6 +1,5 @@
-import { type Config } from "prettier";
 
-const config: Config = {
+const config = {
   trailingComma: "all",
   singleQuote: false,
   printWidth: 80,