package csexp-query

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package csexp-query
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csexp-query

A minimal command-line tool to query canonical s-expressions (csexp) from stdin.

Installation

opam install csexp-query

Usage

csexp-query QUERY

Reads a csexp s-expression from stdin, applies the query, and outputs results (one csexp per line).

Query Operations

Operation

Syntax

Description

field

(field NAME)

Find (NAME value) pairs, return values

index

(index N)

Get Nth element (0-indexed, negative supported)

each

each

Iterate over list elements

pipe

(pipe E1 E2 ...)

Sequential composition

cat

(cat E1 E2 ...)

Concatenate results of independent queries

this

this

Identity

Multiple top-level expressions are implicitly piped.

Examples

# Get a field value
dune describe --format=csexp | csexp-query '(field name)'

# Get the first element
dune describe --format=csexp | csexp-query '(index 0)'

# Iterate over a list field
dune describe --format=csexp | csexp-query '(field modules) each'

# Get multiple fields
dune describe --format=csexp | csexp-query '(cat (field name) (field version))'

# Chain operations
dune describe --format=csexp | csexp-query '(index 0) (field name)'

Query Syntax

The query syntax is compatible with a subset of sexp.

Exit Codes

  • 0: Success (including empty result)
  • 1: Parse error or query error