Add docstring

Author: blegat

docs/Project.toml

@@ -3,4 +3,4 @@ Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
 MultivariatePolynomials = "102ac46a-7ee4-5c85-9060-abc95bfdeaa3"
 
 [compat]
-Documenter = "^0.19.6"
+Documenter = "^0.24.3"

docs/make.jl

@@ -1,8 +1,15 @@
 using Documenter, MultivariatePolynomials
 
 makedocs(
-    format = :html,
     sitename = "MultivariatePolynomials",
+
+    format = Documenter.HTML(
+        # See https://github.com/JuliaDocs/Documenter.jl/issues/868
+        prettyurls = get(ENV, "CI", nothing) == "true"
+    ),
+    # See https://github.com/JuliaOpt/JuMP.jl/issues/1576
+    strict = true,
+
     pages = [
         "Introduction" => "index.md",
         "Types" => "types.md",
@@ -14,9 +21,4 @@ makedocs(
 
 deploydocs(
     repo   = "github.com/JuliaAlgebra/MultivariatePolynomials.jl.git",
-    target = "build",
-    osname = "linux",
-    julia  = "1.0",
-    deps   = nothing,
-    make   = nothing,
 )

docs/src/types.md

@@ -23,6 +23,7 @@ AbstractMonomialLike
 AbstractMonomial
 monomialtype
 variables
+effective_variables
 nvariables
 exponents
 degree
@@ -56,7 +57,7 @@ polynomialtype
 terms
 nterms
 coefficients
-coefficient(p::AbstractPolynomialLike, vars, m::AbstractMonomialLike)
+coefficient(p::AbstractPolynomialLike, m::AbstractMonomialLike, vars)
 monomials
 mindegree
 maxdegree

src/polynomial.jl

@@ -258,7 +258,14 @@ function extdegree(p::Union{AbstractPolynomialLike, AbstractVector{<:AbstractTer
     (mindegree(p, args...), maxdegree(p, args...))
 end
 
-function effective_variables(p::AbstractPolynomialLike, args...)
+"""
+    effective_variables(p::AbstractPolynomialLike)
+
+Return a vector of `eltype` `variable_union_type(p)` (see [`variable_union_type`](@ref)),
+containing all the variables that has nonzero degree in at least one term.
+That is, return all the variables `v` such that `maxdegree(p, v)` is not zero.
+"""
+function effective_variables(p::AbstractPolynomialLike)
     VT = variable_union_type(p)
     return VT[v for v in variables(p) if !iszero(maxdegree(p, v))]
 end