Inspect and edit values with eval, set and diff

§ 1Purpose

Read a single field, change it from the command line, and confirm exactly what changed.

§ 2Prerequisites

• A valid WCL file whose fields you want to read or edit.

§ 3Flowchart

§ 4Steps

$ wcl eval site.wcl service.web.port
80

Run wcl eval site.wcl <dotted.path> (aliased wcl get) to resolve a path from the document root and print its value. Add --json for machine-readable output.

$ wcl set site.wcl service.web.port 9090u32

Run wcl set site.wcl <path> <value> to rewrite the field. wcl set follows the import chain and edits the file that actually declares the field.

$ wcl diff HEAD:site.wcl site.wcl
modified "service:web" {
  field "port" { kind = :changed  old = 80u32  new = 9090u32 }
}

Run wcl diff <old> <new> over the evaluated views to see exactly what changed. Either side may be a <rev>:<path> git specifier, so you can diff the working tree against a committed version.