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DSL preprocessing functions

Source: R/modspec.R
dsl_preprocess.Rd

These functions preprocess model code written in the mrgsolve DSL before C++ compilation.

Usage

convert_pow(x, block = "")

warn_int_div(x, block = "")

convert_fort_if(x)

convert_semicolons(x)

Arguments

x

character vector of source lines to process.

block

model block name; included in warning messages when called during model parsing.

Details

  • convert_pow(): converts Fortran-style exponentiation (**) to C++ pow() calls; runs by default unless turned off by environment variable; lines of code will pass through unaltered if ** is not found.

  • warn_int_div(): warns about literal integer division (e.g. 3/4, 1/2) that truncates toward zero in C++; returns x invisibly and is called for its side-effect warnings; runs by default unless turned off by environment variable.

  • convert_fort_if(): converts Fortran IF/THEN/ELSE/ENDIF constructs and relational operators (.GE., .LE., etc.) to C++; runs only when the nm-vars plugin is invoked.

  • convert_semicolons(): appends semicolons to statement lines that are missing them; lines ending with an operator (e.g., + or / or "=") will not be terminated with a semicolon; this preprocessor must be enlisted through the semicolons plugin and it only runs with nm-vars; the semicolons plugin is brought online when the nm-like composite plugin (nm-vars, autodec, semicolons) is invoked.

Processing is controlled by environment variables:

  • MRGSOLVE_CONVERT_POW (default TRUE)

  • MRGSOLVE_CONVERT_FORT_IF (default TRUE)

  • MRGSOLVE_WARN_INT_DIV (default TRUE)

Set any variable to FALSE to disable the corresponding step when processing a model file via mread(). Adding semicolons must be opted into through the semicolons or nm-like plugins.

Examples

convert_pow("a**2")
#> [1] "pow(a, 2)"
convert_pow("(WT/70) ** THETA(3)")
#> [1] "pow(WT/70, THETA(3))"

code <- c("IF ( WT .GE.90) THEN", "  CL = CL * 0.8", "ENDIF")
cat(code, sep = "\n")
#> IF ( WT .GE.90) THEN
#>   CL = CL * 0.8
#> ENDIF
cat(convert_fort_if(code), sep = "\n")
#> if( WT >= 90) {
#>   CL = CL * 0.8
#> }

convert_semicolons("CL = THETA1")
#> [1] "CL = THETA1;"

code <- c("CL =", "THETA1 *", "(WT/70) *", "exp(ETA(1))")
cat(code, sep = "\n")
#> CL =
#> THETA1 *
#> (WT/70) *
#> exp(ETA(1))
cat(convert_semicolons(code), sep = "\n")
#> CL =
#> THETA1 *
#> (WT/70) *
#> exp(ETA(1));

warn_int_div("THETA(1) * pow(WT/70, 3/4)")
#> Warning: Integer division: '3/4' truncates toward zero; use 3.0/4.0 for real division
warn_int_div("3.0/4")