Package in SystemVerilog

First Example:
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	package my_pkg1;
	int unsigned a = 1;
	endpackage : my_pkg1
	module top1();
	import my_pkg1 :: *;
	initial begin
	$display("my_pkg1::a = %0d", a);
	end
	endmodule : top1
	//Output:
	// my_pkg1::a = 1

view raw sv_pkg1.sv hosted with ❤ by GitHub

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Second Example:
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	package my_pkg1;
	int unsigned a = 1;
	endpackage : my_pkg1
	package my_pkg2;
	import my_pkg1 :: *;
	int unsigned b = 2;
	endpackage : my_pkg2
	module top2();
	//import my_pkg1 :: *;
	import my_pkg2 :: *;
	initial begin
	$display("top : my_pkg1::a = %0d, my_pkg2::b = %0d", a, b);
	end
	endmodule : top2
	//Output:
	// Identifier 'a' has not been declared yet. If this error is not expected, please check if you have set `default_nettype to none.

view raw sv_pkg2.sv hosted with ❤ by GitHub

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Third Example:
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	package my_pkg1;
	int unsigned a = 1;
	endpackage : my_pkg1
	package my_pkg2;
	import my_pkg1 :: *;
	int unsigned b = 2;
	endpackage : my_pkg2
	module top3();
	import my_pkg1 :: *;
	import my_pkg2 :: *;
	initial begin
	$display("top : my_pkg1::a = %0d, my_pkg2::b = %0d", a, b);
	end
	endmodule : top3
	//Output:
	// top : my_pkg1::a = 1, my_pkg2::b = 2

view raw sv_pkg3.sv hosted with ❤ by GitHub

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Fourth Example:
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	package my_pkg1;
	int unsigned a = 1;
	endpackage : my_pkg1
	package my_pkg2;
	import my_pkg1 :: *;
	int unsigned b = 2;
	function void pkg2_print();
	$display("my_pkg2 : pkg2_print : my_pkg1::a = %0d, my_pkg2::b = %0d", a, b);
	endfunction : pkg2_print
	endpackage : my_pkg2
	module top4();
	import my_pkg2 :: *;
	initial begin
	void '(pkg2_print());
	end
	endmodule : top4
	//Output:
	// my_pkg2 : pkg2_print : my_pkg1::a = 1, my_pkg2::b = 2

view raw sv_pkg4.sv hosted with ❤ by GitHub

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Fifth Example:
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	package my_pkg1;
	int unsigned a = 1;
	endpackage : my_pkg1
	package my_pkg2;
	import my_pkg1 :: *;
	int unsigned b = 2;
	function void pkg2_print();
	$display("my_pkg2 : pkg2_print : my_pkg1::a = %0d, my_pkg2::b = %0d", a, b);
	endfunction : pkg2_print
	endpackage : my_pkg2
	package my_pkg3;
	//import my_pkg1 :: *;
	import my_pkg2 :: *;
	int unsigned c = 3;
	function void pkg3_print();
	$display("my_pkg3 : pkg3_print : my_pkg1::a = %0d, my_pkg2::b = %0d, my_pkg3::c = %0d", a, b, c);
	endfunction : pkg3_print
	endpackage : my_pkg3
	module top5();
	import my_pkg3 :: *;
	initial begin
	void '(pkg3_print());
	end
	endmodule : top5
	//Output:
	// Identifier 'a' has not been declared yet. If this error is not expected, please check if you have set `default_nettype to none

view raw sv_pkg5.sv hosted with ❤ by GitHub

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Sixth Example:
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	package my_pkg1;
	int unsigned a = 1;
	endpackage : my_pkg1
	package my_pkg2;
	import my_pkg1 :: *;
	int unsigned b = 2;
	function void pkg2_print();
	$display("my_pkg2 : pkg2_print : my_pkg1::a = %0d, my_pkg2::b = %0d", a, b);
	endfunction : pkg2_print
	endpackage : my_pkg2
	package my_pkg3;
	import my_pkg1 :: *;
	import my_pkg2 :: *;
	int unsigned c = 3;
	function void pkg3_print();
	$display("my_pkg3 : pkg3_print : my_pkg1::a = %0d, my_pkg2::b = %0d, my_pkg3::c = %0d", a, b, c);
	endfunction : pkg3_print
	endpackage : my_pkg3
	module top6();
	import my_pkg3 :: *;
	initial begin
	void '(pkg3_print());
	end
	endmodule : top6
	//Output:
	// my_pkg3 : pkg3_print : my_pkg1::a = 1, my_pkg2::b = 2, my_pkg3::c = 3

view raw sv_pkg6.sv hosted with ❤ by GitHub

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Seventh Example:
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	package my_pkg1;
	int unsigned a = 1;
	endpackage : my_pkg1
	package my_pkg2;
	import my_pkg1 :: *;
	int unsigned b = 2;
	function void pkg2_print();
	$display("my_pkg2 : pkg2_print : my_pkg1::a = %0d, my_pkg2::b = %0d", a, b);
	endfunction : pkg2_print
	endpackage : my_pkg2
	package my_pkg3;
	//import my_pkg1 :: *;
	import my_pkg2 :: *;
	int unsigned c = 3;
	function void pkg3_print();
	$display("my_pkg3 : pkg3_print : my_pkg3::c = %0d", c);
	$display("calling my_pkg2 :: pkg2_print");
	pkg2_print();
	endfunction : pkg3_print
	endpackage : my_pkg3
	module top7();
	import my_pkg3 :: *;
	initial begin
	void '(pkg3_print());
	end
	endmodule : top7
	//Output:
	// my_pkg3 : pkg3_print : my_pkg3::c = 3
	// calling my_pkg2 :: pkg2_print
	// my_pkg2 : pkg2_print : my_pkg1::a = 1, my_pkg2::b = 2

view raw sv_pkg7.sv hosted with ❤ by GitHub

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Eighth Example: (package and module having variable with same name)

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	package my_pkg1;
	int unsigned a = 1;
	endpackage : my_pkg1
	module top();
	int unsigned a = 2;
	import my_pkg1 :: *;
	initial begin
	$display ("a=%0d", a);
	$display ("my_pkg1::a=%0d", my_pkg1::a);
	end
	endmodule : top
	//Output:
	// a=2
	// my_pkg1::a=1

view raw sv_pkg8.sv hosted with ❤ by GitHub

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Ninth Example: (package and module having variable with same name)

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	package my_pkg1;
	int unsigned a = 1;
	endpackage : my_pkg1
	module top();
	// Not importing my_pkg1 here
	int unsigned a = 2;
	initial begin
	$display ("a=%0d", a);
	$display ("my_pkg1::a=%0d", my_pkg1::a);
	end
	endmodule : top
	//Output:
	// a=2
	// my_pkg1::a=1

view raw sv_pkg9.sv hosted with ❤ by GitHub

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