Substitute metadata tokens in text — apply

Replaces `glue`-style `{token}` placeholders in a character vector with values taken from a user-controlled `metadata` list. This lets study-level information (e.g. study number, data cut-off date) be injected into slide titles, footnotes and placeholder slides without editing the deck or the spec text directly.

Usage

apply_tokens(text, metadata = NULL)

Arguments

text: `character` vector possibly containing `{token}` placeholders.
metadata: Named `list` (or `NULL`) supplying token values. Typically the spec entry produced by [read_spec()], into which the `metadata` argument has already been merged.

Value

A length-one `character` (`glue`) value with tokens substituted and the input collapsed by newlines, matching the previous `glue::glue()` behavior.

Details

Token values are looked up first in `metadata`, then in the calling environment (preserving the existing `glue` behavior used across `decorate` methods). A `{token}` that resolves to neither raises an informative error, so typos are caught early rather than silently producing a broken slide.

Examples

apply_tokens("Demographics - Study {study}", list(study = "BP12345"))
#> Demographics - Study BP12345
apply_tokens(c("Line 1 {study}", "Line 2"), list(study = "BP12345"))
#> Line 1 BP12345
#> Line 2