moxieport - Plan

Mechanical Go-to-Moxie source transformer. Uses the Moxie compiler's own parser (compile.ParseFile), rewrites the AST in-place, emits transformed source, produces a semantic report of constructs requiring manual intervention.

Status: v1 complete

All 11 mechanical transforms implemented and verified. Round-trip test (parse->print->parse->print->diff) passes with zero diff. Installed at ~/.local/bin/moxieport.

Known upstream bug: os.Args broken

os.Args is always empty in standalone Moxie binaries. Root cause: os.runtime_args (defined in runtime_unix.mx via //go:linkname) is not compiled into sysroot/runtime.bc. The runtime.initAll() function generated by the compiler calls os.runtime_args() and stores the result in os.Args, but since the function doesn't exist in the binary, initAll compiles to just ret. moxieport works around this by reading /proc/self/cmdline.

Location

/home/mleku/s/moxie/moxieport/ - new package, single binary.

Three components

1. AST Printer (largest piece)

Print(w io.Writer, f *compile.File) - walks a *File and emits syntactically valid Moxie source. Must handle all node types in compile/nodes.mx:

• Declarations: ImportDecl, ConstDecl, TypeDecl, VarDecl, FuncDecl
• Expressions: Name, BasicLit, CallExpr, SelectorExpr, IndexExpr, SliceExpr, Operation, CompositeLit, KeyValueExpr, FuncLit, AssertExpr, ParenExpr, ListExpr
• Types: ArrayType, SliceType, StructType, InterfaceType, FuncType, MapType, ChanType, DotsType
• Statements: BlockStmt, ExprStmt, SendStmt, AssignStmt, ReturnStmt, IfStmt, ForStmt, RangeClause, SwitchStmt, CaseClause, SelectStmt, CommClause, BranchStmt, LabeledStmt, CallStmt, DeclStmt, EmptyStmt

No comment preservation (parser discards them). Pragmas (//go: directives, //export) preserved via Pragma fields on nodes.

2. AST Transforms (mechanical, deterministic)

Each transform is func(f *compile.File), mutates AST in-place, applied in sequence before printing.

#	Transform	AST pattern	Rewrite to
1	int width	Name.Value == "int" in type or conversion position	"int64"
2	uint width	Name.Value == "uint" in type or conversion position	"uint64"
3	make slice	CallExpr where Fun is Name{"make"}, first arg is SliceType	CompositeLit with SliceType + colon-length syntax
4	make chan	CallExpr where Fun is Name{"make"}, first arg is ChanType	CompositeLit with ChanType + optional buffer arg
5	make map	CallExpr where Fun is Name{"make"}, first arg is MapType	CompositeLit with MapType
6	new(T)	CallExpr where Fun is Name{"new"}	Operation{Op: And, X: CompositeLit{Type: T}} (i.e. &T{})
7	string concat	Operation{Op: Add} where operands are StringLit	Change Op to Or (pipe). Conservative: only rewrite when at least one operand is StringLit. Flag X + Y where neither is a literal.
8	strings import	ImportDecl with Path.Value == "strings"	Change to "bytes"
9	fallthrough	BranchStmt{Tok: Fallthrough} in CaseClause	Merge this clause's Cases with next clause's Cases, combine bodies, remove the BranchStmt
10	init rename	FuncDecl with Name.Value == "init"	Rename to init_N, add CallExpr at top of main()
11	file extension	Output filename	.go -> .mx

Match on Name.Value must be exact-equal, not prefix (avoid mangling int32, int64, uint16, etc.).

3. Semantic Reporter

Walk the transformed AST. One line per flag, file:line:col + construct. Machine-parseable for claude code consumption.

Flag	Detection
interface{} / any	InterfaceType with empty MethodList, or Name.Value == "any"
reflect import	ImportDecl path contains "reflect"
go statement	CallStmt{Tok: Go}
sync.* import	ImportDecl path contains "sync"
context import	ImportDecl path contains "context"
uintptr	Name.Value == "uintptr" in type position
complex64/128	Name.Value matches "complex64" or "complex128"
unsafe import	ImportDecl path is "unsafe"
Package-level var	VarDecl at top-level DeclList
Remaining + on unknown types	Operation{Op: Add} not rewritten by transform #7

Build order

1. AST Printer - implement and verify round-trip: parse a .mx file, print it, parse the output, compare AST structure. Validates the printer independently of transforms.
2. Transforms - one at a time, each verified by: parse Go file -> transform -> print -> parse output -> verify target pattern is gone.
3. Reporter - walks the already-transformed AST, outputs the checklist.
4. CLI - moxieport <file.go> writes <file.mx> + prints report to stderr. moxieport <dir>/ processes all .go files.

Pre-build investigation

Before writing the printer, read how the parser represents CompositeLit with colon-length syntax ([]T{:n}, []T{:n:c}, chan T{n}). The AST representation determines:

• How the printer emits these constructs
• How the make-to-literal transform constructs its output nodes

Check the parser's compositeLit / complitexpr handling to determine whether the colon-length form uses KeyValueExpr with a nil key, a dedicated node type, or some other encoding. Do not assume the structure.

What moxieport does NOT do

• No type checking. Raw parsed AST only.
• No semantic transformation. Does not convert goroutine patterns to spawn/channel.
• No dependency resolution. Processes files individually.
• No formatting opinions beyond faithful AST emission. Indentation follows block depth.

Value

• Eliminates mechanical drudgery of Go-to-Moxie porting (90% of keystrokes, 0% of thinking).
• Exercises the self-hosted compiler's parser through a non-compilation use case.
• Semantic report turns "port this Go package" from open-ended conversation into bounded checklist with file:line locations for claude code.