String literal with single-quotes causes error "Variable not found"

[feelosophy13]

Variable comparison inside a template throws an error. Below is a reproducible example.

R code

library(jinjar)

render(
  fs::path("template.txt"),
  variable = 'test'
)

Template file template.txt

{# this works #}
{% if 1 == 1 %}
  {{ variable }}
{% endif %}

{# this does NOT work #}
{% if variable == 'test' %}
  {{ variable }}
{% endif %}

Error

Error in `render()`:
! Problem encountered while rendering template.
Caused by error:
! Variable 'test' not found.
ℹ Error occurred on line 7 and column 20.
Run `rlang::last_trace()` to see where the error occurred.

Session information

R version 4.3.1 (2023-06-16)
Platform: x86_64-apple-darwin20 (64-bit)
Running under: macOS Ventura 13.5

Matrix products: default
BLAS:   /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib 
LAPACK: /Library/Frameworks/R.framework/Versions/4.3-x86_64/Resources/lib/libRlapack.dylib;  LAPACK version 3.11.0

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

time zone: America/Los_Angeles
tzcode source: internal

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] jinjar_0.3.1   jsonlite_1.8.7

loaded via a namespace (and not attached):
 [1] utf8_1.2.4        R6_2.5.1          xfun_0.41         tidyselect_1.2.0  magrittr_2.0.3    glue_1.6.2        tibble_3.2.1      knitr_1.45       
 [9] pkgconfig_2.0.3   dplyr_1.1.3       generics_0.1.3    lifecycle_1.0.3   cli_3.6.1         fansi_1.0.5       vctrs_0.6.4       DBI_1.1.3        
[17] compiler_4.3.1    rstudioapi_0.15.0 tools_4.3.1       pillar_1.9.0      fs_1.6.3          rlang_1.1.1      

[davidchall]

This error is caused by the right-hand side of the comparison. The template syntax only supports string literals specified using double-quotes (not single-quotes). This is an unfortunate consequence of the underlying usage of JSON objects.

In your example, you should use "test" instead of 'test'. Here's a quick demo:

library(jinjar)

render("{{ x == 'test' }}", x = "test")
#> Error in `render()` at jinjar/R/render.R:44:2:
#> ! Problem encountered while rendering template.
#> Caused by error:
#> ! Variable 'test' not found.
#> ℹ Error occurred on line 1 and column 10.

render('{{ x == "test" }}', x = "test")
#> [1] "true"

^{Created on 2023-11-09 with reprex v2.0.2}

[feelosophy13]

Thank you! Great package, by the way! :D