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Stable SipHash-1-3 of code

Source: R/hashing.R
st_hash_code.Rd

Computes a stable hash of R code (functions, expressions, or character vectors). For functions, includes both formals (arguments) and body. Whitespace is lightly normalized to reduce spurious differences. That means code changes which only alter the number of spaces in strings (e.g. "a b" vs "a b") will produce identical hashes.

Usage

st_hash_code(code)

Arguments

code

A function, expression (language object), or character vector

Value

Lowercase hex string (16 hex characters) from siphash13().

Normalization

The code undergoes light normalization before hashing:

  • Multiple spaces/tabs collapsed to single space

  • Line endings normalized to \n

  • This reduces false positives from formatting changes while preserving code structure

What Gets Hashed

  • Functions: formals (argument list) + body (code)

  • Expressions/language: deparsed code

  • Character vectors: concatenated with newlines

Examples

if (FALSE) { # \dontrun{
# Hash a function
st_hash_code(function(x) x + 1)

# Hash an expression
st_hash_code(quote(x + 1))

# Hash character code
st_hash_code("x <- 1\ny <- 2")
} # }