R targets包执行报错排查：unexpected '/'错误及tikzLatex配置问题

一、Targets管道运行错误 #

错误信息 #

✖ error target quantities_plot_base
• end pipeline [3.558 seconds]
Error:

! Error running targets::tar_make()
  
Target errors: targets::tar_meta(fields = error, complete_only = TRUE)
  
Tips: https://books.ropensci.org/targets/debugging.html
  
Last error: <text>:1:2: unexpected '/'

1: +/

     ^

关联代码 #

对应的target定义：

tar_target(
    name = quantities_plot_base,
    command = powerscale_seq_summ_plot(sensitivity_sequence_base)
  )

powerscale_seq_summ_plot函数代码：

powerscale_seq_summ_plot <- function(powerscale_seq) {

  powerscale_plot_quantities(powerscale_seq, variables = "b_wrist", quantities = c("mean", "sd"), mcse = TRUE) +
    ggplot2::facet_wrap(
      . ~ quantity,
      scales = "free",
      ncol = 3,
      labeller = ggplot2::as_labeller(
        c(
          "b_wrist" = "",
          "sd" = "SD",
          "mean" = "Mean",
          "cjs_dist" = "$\\text{CJS}_{\\text{dist}}$"
        )
      )
    ) +
    guides(colour = "none") +
    xlab("Power-scaling $\\alpha$") +
    scale_color_manual(values = rep("black", 3)) +
    scale_shape_manual(values = c("prior" = 15, "likelihood" = 22), labels = c("Prior power-scaling", "Likelihood power-scaling"), name = NULL) +
    scale_linetype_manual(values = "dashed", labels = "$\\pm2$ MCSE", name = NULL) +
    cowplot::theme_half_open() +
    theme(
      legend.position = "bottom",
      legend.text = element_text(size = 10),
      axis.text = element_text(size = 10),
      axis.title = element_text(size = 10),
      strip.text = element_text(size = 10),
      strip.background = element_blank(),
      legend.text.align = 0,
      axis.line.y = element_blank(),
      axis.ticks.y = element_line(colour = "black"),
      axis.line.x = element_blank(),
      axis.ticks.x = element_line(colour = "black"),
      legend.title = element_text(size = 10),
      aspect.ratio = 1
    ) +
    cowplot::panel_border(color = "black", size = 1)
}

错误排查点 #

错误提示unexpected '/'指向+/，说明ggplot链式操作的某个+后存在语法错误，核心问题在LaTeX公式的字符串转义：

• R字符串中反斜杠\是转义字符，因此LaTeX命令里的\text、\alpha等需要写成\\text、\\alpha，否则R会将单个\解析为转义，导致字符串结构混乱，进而引发+后的语法错误。
• 修正函数中所有包含LaTeX的字符串：比如"$\text{CJS}_{\text{dist}}$"改为"$\\text{CJS}_{\\text{dist}}$"，"Power-scaling $\alpha$"改为"Power-scaling $\\alpha$"，"$\pm2$ MCSE"改为"$\\pm2$ MCSE"。

二、TikZ LaTeX配置不生效问题 #

配置代码 #

options(
  tizkDocumentDelcaration = "\documentclass[10pt]{article}",
  tikzLatexPackages = c(
    getOption("tikzLatexPackages"),
    "\usepackage{tikz}",
    "\usepackage{amsmath}",
    "\usepackage{amsfonts}",
    "\usepackage{bm}",
    "\usepackage{lmodern}",
    "\usepackage{multirow}",
    "\usepackage[T1]{fontenc}",
    "\usepackage{textcomp}",
    "\usepackage{microtype}",
    "\DeclareMathOperator{\normal}{normal}",
    "\DeclareMathOperator{\Bernoulli}{Bernoulli}",
    "\DeclareMathOperator{\gammadist}{gamma}",
    "\DeclareMathOperator{\expdist}{exponential}",
    "\DeclareMathOperator{\betadist}{beta}",
    "\DeclareMathOperator{\Cauchy}{Cauchy}"
  )
)

问题排查 #

配置存在两处关键错误导致失效：

1. 拼写错误：tizkDocumentDelcaration应为tikzDocumentDeclaration（tizk拼写错误，Delcaration应为Declaration）；
2. 字符串转义错误：所有LaTeX命令前的\需要改为\\，比如"\documentclass[10pt]{article}"改为"\\documentclass[10pt]{article}"；
3. 确保已安装并加载tikzDevice包，否则配置选项无法生效。

内容的提问来源于stack exchange，提问作者Chachi