From b526a2ed52ca47145bbea414e394540a05c31b19 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <tahvdbrand@gmail.com>
Date: Mon, 8 Apr 2024 16:04:06 +0200
Subject: [PATCH 1/7] format signed numbers

---
 R/label-log.R | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/R/label-log.R b/R/label-log.R
index 802d2a13..905c7668 100644
--- a/R/label-log.R
+++ b/R/label-log.R
@@ -12,14 +12,25 @@
 #' @examples
 #' demo_log10(c(1, 1e5), labels = label_log())
 #' demo_log10(c(1, 1e5), breaks = breaks_log(base = 2), labels = label_log(base = 2))
-label_log <- function(base = 10, digits = 3) {
+label_log <- function(base = 10, digits = 3, signed = NULL) {
   function(x) {
     if (length(x) == 0) {
       return(expression())
     }
+    prefix <- rep("", length(x))
+    signed <- signed %||% if (any(is.finite(x))) any(x <= 0) else FALSE
+    if (signed) {
+      sign <- sign(x)
+      prefix[sign == +1] <- "+"
+      prefix[sign == -1] <- "-"
+      x <- abs(x)
+    }
 
-    exponent <- format(log(x, base = base), digits = digits)
-    text <- paste0(base, "^", exponent)
+    exponent <- format(zapsmall(log(x, base = base)), digits = digits)
+    text <- paste0(prefix, base, "^", exponent)
+    if (signed) {
+      text[x == 0] <- "0"
+    }
     ret <- parse_safe(text)
 
     # restore NAs from input vector

From d0fc2d3a925577c5115b6f543d55726f34181046 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <tahvdbrand@gmail.com>
Date: Mon, 8 Apr 2024 16:04:37 +0200
Subject: [PATCH 2/7] document

---
 R/label-log.R    | 3 +++
 man/label_log.Rd | 6 +++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/R/label-log.R b/R/label-log.R
index 905c7668..2bc62ca9 100644
--- a/R/label-log.R
+++ b/R/label-log.R
@@ -5,6 +5,9 @@
 #' @param base Base of logarithm to use
 #' @param digits Number of significant digits to show for the exponent. Argument
 #'   is passed on to [base::format()].
+#' @param signed Should a `+` or `-` be displayed as a prefix? The
+#'   default, `NULL`, displays signs if there are zeroes or negative numbers
+#'   present.
 #' @inherit label_number return
 #' @seealso [breaks_log()] for the related breaks algorithm.
 #' @export
diff --git a/man/label_log.Rd b/man/label_log.Rd
index daf576fb..9c9cf999 100644
--- a/man/label_log.Rd
+++ b/man/label_log.Rd
@@ -4,13 +4,17 @@
 \alias{label_log}
 \title{Label numbers in log format (10^3, 10^6, etc)}
 \usage{
-label_log(base = 10, digits = 3)
+label_log(base = 10, digits = 3, signed = NULL)
 }
 \arguments{
 \item{base}{Base of logarithm to use}
 
 \item{digits}{Number of significant digits to show for the exponent. Argument
 is passed on to \code{\link[base:format]{base::format()}}.}
+
+\item{signed}{Should a \code{+} or \code{-} be displayed as a prefix? The
+default, \code{NULL}, displays signs if there are zeroes or negative numbers
+present.}
 }
 \value{
 All \code{label_()} functions return a "labelling" function, i.e. a function that

From fb0c9eea49b818c9486090bb8500eb7838ad5129 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <tahvdbrand@gmail.com>
Date: Mon, 8 Apr 2024 16:04:43 +0200
Subject: [PATCH 3/7] add test

---
 tests/testthat/test-label-log.R | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/testthat/test-label-log.R b/tests/testthat/test-label-log.R
index 0a555ae0..2aee4f49 100644
--- a/tests/testthat/test-label-log.R
+++ b/tests/testthat/test-label-log.R
@@ -5,4 +5,5 @@ test_that("label_log() returns expression", {
   expect_equal(label_log()(c(0.1, 10)), expression(10^-1, 10^1))
   expect_equal(label_log(base = 2)(8), expression(2^3))
   expect_equal(label_log(base = 2, digits = 3)(7), expression(2^2.81))
+  expect_equal(label_log(signed = TRUE)(c(-100, 100)), expression(-10^2, +10^2))
 })

From 89e9e9274404230d8257807327831c9b7ed0e7e0 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <tahvdbrand@gmail.com>
Date: Mon, 8 Apr 2024 16:05:41 +0200
Subject: [PATCH 4/7] add news bullet

---
 NEWS.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/NEWS.md b/NEWS.md
index 9646d4a5..6e2d1bb7 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,8 @@
 # scales (development version)
 
+* `label_log()` has a `signed` argument for displaying negative numbers 
+  (@teunbrand, #421).
+
 # scales 1.3.0
 
 ## Better type support

From 9215dc14208154c6144cb272afd8b23169d30cef Mon Sep 17 00:00:00 2001
From: Teun van den Brand <tahvdbrand@gmail.com>
Date: Tue, 16 Apr 2024 13:05:27 +0200
Subject: [PATCH 5/7] deal with non-finite numbers better

---
 R/label-log.R | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/R/label-log.R b/R/label-log.R
index 2bc62ca9..9f48289a 100644
--- a/R/label-log.R
+++ b/R/label-log.R
@@ -21,7 +21,8 @@ label_log <- function(base = 10, digits = 3, signed = NULL) {
       return(expression())
     }
     prefix <- rep("", length(x))
-    signed <- signed %||% if (any(is.finite(x))) any(x <= 0) else FALSE
+    xfinite <- x[is.finite(x)]
+    signed <- signed %||% any(xfinite <= 0)
     if (signed) {
       sign <- sign(x)
       prefix[sign == +1] <- "+"

From a2990740b5258d40c515f53205fa9f99ceb5cf83 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <tahvdbrand@gmail.com>
Date: Fri, 4 Oct 2024 12:50:11 +0200
Subject: [PATCH 6/7] isolate formatting function

---
 DESCRIPTION      |  2 +-
 NAMESPACE        |  1 +
 R/label-log.R    | 57 ++++++++++++++++++++++++++++++------------------
 man/label_log.Rd |  9 +++++++-
 4 files changed, 46 insertions(+), 23 deletions(-)

diff --git a/DESCRIPTION b/DESCRIPTION
index 38d99259..0ee8fe58 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -39,4 +39,4 @@ Config/testthat/edition: 3
 Encoding: UTF-8
 LazyLoad: yes
 Roxygen: list(markdown = TRUE, r6 = FALSE)
-RoxygenNote: 7.2.3
+RoxygenNote: 7.3.2
diff --git a/NAMESPACE b/NAMESPACE
index 115ded97..efa1bf22 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -83,6 +83,7 @@ export(exp_trans)
 export(expand_range)
 export(extended_breaks)
 export(format_format)
+export(format_log)
 export(fullseq)
 export(gradient_n_pal)
 export(grey_pal)
diff --git a/R/label-log.R b/R/label-log.R
index 9f48289a..0e5321bd 100644
--- a/R/label-log.R
+++ b/R/label-log.R
@@ -1,6 +1,8 @@
 #' Label numbers in log format (10^3, 10^6, etc)
 #'
-#' `label_log()` displays numbers as base^exponent, using superscript formatting.
+#' `label_log()` and `format_log()` display numbers as base^exponent, using
+#' superscript formatting. `label_log()` returns expressions suitable for
+#' labelling in scales, whereas `format_log()` returns deparsed text.
 #'
 #' @param base Base of logarithm to use
 #' @param digits Number of significant digits to show for the exponent. Argument
@@ -8,6 +10,7 @@
 #' @param signed Should a `+` or `-` be displayed as a prefix? The
 #'   default, `NULL`, displays signs if there are zeroes or negative numbers
 #'   present.
+#' @param ... Passed on to `format()`.
 #' @inherit label_number return
 #' @seealso [breaks_log()] for the related breaks algorithm.
 #' @export
@@ -15,31 +18,43 @@
 #' @examples
 #' demo_log10(c(1, 1e5), labels = label_log())
 #' demo_log10(c(1, 1e5), breaks = breaks_log(base = 2), labels = label_log(base = 2))
+#' format_log(c(0.1, 1, 10))
 label_log <- function(base = 10, digits = 3, signed = NULL) {
   function(x) {
-    if (length(x) == 0) {
-      return(expression())
-    }
-    prefix <- rep("", length(x))
-    xfinite <- x[is.finite(x)]
-    signed <- signed %||% any(xfinite <= 0)
-    if (signed) {
-      sign <- sign(x)
-      prefix[sign == +1] <- "+"
-      prefix[sign == -1] <- "-"
-      x <- abs(x)
-    }
-
-    exponent <- format(zapsmall(log(x, base = base)), digits = digits)
-    text <- paste0(prefix, base, "^", exponent)
-    if (signed) {
-      text[x == 0] <- "0"
-    }
+    text <- format_log(x, base = base, signed = signed, digits = digits)
     ret <- parse_safe(text)
-
     # restore NAs from input vector
     ret[is.na(x)] <- NA
-
     ret
   }
 }
+
+#' @export
+#' @rdname label_log
+format_log <- function(x, base = 10, signed = NULL, ...) {
+
+  if (length(x) == 0) {
+    return(character())
+  }
+  prefix <- rep("", length(x))
+  finites <- x[is.finite(x)]
+
+  signed <- signed %||% any(finites <= 0)
+  if (signed) {
+    sign <- sign(x)
+    prefix[sign == +1] <- "+"
+    prefix[sign == -1] <- "-"
+    x <- abs(x)
+    x[x == 0] <- 1
+  }
+
+  exponent <- format(zapsmall(log(x, base = base)), ...)
+  text <- paste0(prefix, base, "^", exponent)
+
+  if (signed) {
+    text[sign == 0] <- "0"
+  }
+  text[is.na(x)] <- NA
+
+  text
+}
diff --git a/man/label_log.Rd b/man/label_log.Rd
index 9c9cf999..ebca3496 100644
--- a/man/label_log.Rd
+++ b/man/label_log.Rd
@@ -2,9 +2,12 @@
 % Please edit documentation in R/label-log.R
 \name{label_log}
 \alias{label_log}
+\alias{format_log}
 \title{Label numbers in log format (10^3, 10^6, etc)}
 \usage{
 label_log(base = 10, digits = 3, signed = NULL)
+
+format_log(x, base = 10, signed = NULL, ...)
 }
 \arguments{
 \item{base}{Base of logarithm to use}
@@ -15,6 +18,8 @@ is passed on to \code{\link[base:format]{base::format()}}.}
 \item{signed}{Should a \code{+} or \code{-} be displayed as a prefix? The
 default, \code{NULL}, displays signs if there are zeroes or negative numbers
 present.}
+
+\item{...}{Passed on to \code{format()}.}
 }
 \value{
 All \code{label_()} functions return a "labelling" function, i.e. a function that
@@ -27,7 +32,9 @@ they work similarly for all scales, including those that generate legends
 rather than axes.
 }
 \description{
-\code{label_log()} displays numbers as base^exponent, using superscript formatting.
+\code{label_log()} and \code{format_log()} display numbers as base^exponent, using
+superscript formatting. \code{label_log()} returns expressions suitable for
+labelling in scales, whereas \code{format_log()} returns deparsed text.
 }
 \examples{
 demo_log10(c(1, 1e5), labels = label_log())

From 9e6d5d19dafc085571e8de697b5501ba25c2905e Mon Sep 17 00:00:00 2001
From: Teun van den Brand <tahvdbrand@gmail.com>
Date: Fri, 4 Oct 2024 12:56:41 +0200
Subject: [PATCH 7/7] lol at my incompetence

---
 R/label-log.R    | 2 ++
 man/label_log.Rd | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/R/label-log.R b/R/label-log.R
index 0e5321bd..e31e2bb8 100644
--- a/R/label-log.R
+++ b/R/label-log.R
@@ -4,6 +4,8 @@
 #' superscript formatting. `label_log()` returns expressions suitable for
 #' labelling in scales, whereas `format_log()` returns deparsed text.
 #'
+#'
+#' @param x A numeric vector to format
 #' @param base Base of logarithm to use
 #' @param digits Number of significant digits to show for the exponent. Argument
 #'   is passed on to [base::format()].
diff --git a/man/label_log.Rd b/man/label_log.Rd
index ebca3496..d0dee6ab 100644
--- a/man/label_log.Rd
+++ b/man/label_log.Rd
@@ -19,6 +19,8 @@ is passed on to \code{\link[base:format]{base::format()}}.}
 default, \code{NULL}, displays signs if there are zeroes or negative numbers
 present.}
 
+\item{x}{A numeric vector to format}
+
 \item{...}{Passed on to \code{format()}.}
 }
 \value{
@@ -39,6 +41,7 @@ labelling in scales, whereas \code{format_log()} returns deparsed text.
 \examples{
 demo_log10(c(1, 1e5), labels = label_log())
 demo_log10(c(1, 1e5), breaks = breaks_log(base = 2), labels = label_log(base = 2))
+format_log(c(0.1, 1, 10))
 }
 \seealso{
 \code{\link[=breaks_log]{breaks_log()}} for the related breaks algorithm.