pascalscript

Read-only parser + symbolic disassembler for the RemObjects PascalScript III binary container format (IFPS magic). Inno Setup [Code] sections are the most prominent embedding, but the format is general: any Delphi application that vendors RemObjects PascalScript can produce these blobs.

What it does

• Validates the 28-byte fixed TPSHeader (magic, build number, table counts, main-proc index).
• Walks the variable-length type, proc, var, and build-21+ attribute tables into typed Rust views with borrowed string slices (no allocation outside the small per-table Vecs).
• Decodes the bytecode stream (27 documented opcodes plus cm_nop) into typed Instructions, with PC-relative branches resolved to absolute offsets.
• Renders a symbolic disassembly via Container::display(...) with operand indices resolved against the symbol tables (g#7 → g_AppId, proc#12 → RegSetValueEx, etc.).

What it doesn't do

• No execution. This is a read-only parser; no interpreter, no JIT.
• No re-encoding. No serializer.
• No decompilation to Pascal source. The output is an annotated linear listing of opcodes, not reconstructed Pascal.
• No host-API name mapping. Imported externals appear as the names the host application registered them under (e.g. Inno's SHELLEXEC, EXPANDCONSTANT); semantic descriptions of those names are the host's responsibility.

Wire-format reference

Every parser file cites the upstream Pascal line range it mirrors. Canonical anchors:

• IFPS magic: Components/UniPs/Source/uPSUtils.pas:20
• Header: uPSRuntime.pas:1204-1212
• BaseType constants: uPSUtils.pas:46-118
• Container deserializer (TPSExec.LoadData): uPSRuntime.pas:2318-3033
• Opcode set: uPSUtils.pas:122-297
• Operand wire form (TPSExec.ReadVariable): uPSRuntime.pas:6700+

Pinned upstream revision: see Components/UniPs/rev.txt in any recent issrc checkout.

Adversarial-input safety

unsafe_code, clippy::unwrap_used, expect_used, panic, arithmetic_side_effects, and indexing_slicing are all denied at crate level. Every read goes through an internal cursor that surfaces truncation as an Error::Truncated rather than panicking.

License

Apache-2.0.